A bibliometric analysis of Economic Research-Ekonomska Istraživanja (2007–2019)

Abstract Economic Research-Ekonomska Istraživanja is an international journal in the research field of business and economics and firstly published in 2007. In this paper, we make a bibliometric analysis of publications in Economic Research-Ekonomska Istraživanja from 2007 to 2019. According to Web of Science (WoS), we derive 831 publications in the journal after data pre-processing. First, we explore characteristics of publications and citations based on widely recognised bibliometric indicators. Second, we present the influential countries/regions and influential institutions of publications in the journal. Next, we illustrate science mapping analysis according to two visualisation tools that are VOS viewer and CiteSpace. Specifically, co-citation networks and co-authorship networks are conducted to analyse connection of items. We generate bust detection analysis to identify the emerging cited authors and cited journals. Co-occurrence analysis and timeline view analysis of keywords are developed to detect the hot topics and trend of the journal. Finally, we make some discussions about future challenges of the journal in terms of the above analysis. This paper helps in objectively understanding the development of Economic Research-Ekonomska Istraživanja and provides a valuable reference for the scholars in business and economics.


Introduction
Bibliometrics is a scientific research area, and it has attracted more and more attention by the scientific community (Alvarez-Betancourt & Garcia-Silvente, 2014). So far, bibliometric analysis has developed rapidly and applied to many research fields, because it is an effective way to evaluate the merits of a given subject area or a certain journal (Shang et al., 2015). The reason is that bibliometrics is a discipline with the extensive intersection and combination of philology, information science, mathematics and statistics in a specific area (He et al., 2017), and the evolution of a particular research direction can be better revealed by using bibliometric indicators.
Because of its special advantages, bibliometrics has a wide range of applications in various fields, such as business and economics (Merigo et al., 2016), fuzzy decision making (Liu & Liao, 2017), sustainable energy (Hache & Palle, 2019) and supply chain of renewable energy (Azevedo et al., 2019). Besides, the publications' structure and the development trend of a journal can be explored based on bibliometric analysis, and scholars have preferred to systematically research journals in recent years. For example, the evolution of Technological and Economic Development of Economy was developed according to bibliometric analysis (Yu et al., 2019). An overview on the publications of European Journal of Operational Research was provided through bibliometric indicators (Laengle et al., 2017). A bibliometric analysis of the documents published in Information Sciences was made to celebrate its 50 th anniversary . The structure and citation landscape of IEEE Transaction on Fuzzy Systems was explored based on a rigorous analytical approach (Yu et al., 2018). A bibliometric overview of International Journal of Strategic Property Management was studied (Zhou et al., 2019), and a bibliometric analysis of International Journal of Computers Communications and Control was developed to research the trend .
Science mapping analysis is one of the most important methods in bibliometrics, because it helps scholars understand research trends greatly and intuitively see the structure and the trend of a research field or a journal (Cobo et al., 2011). For example, a general bibliometric overview of the major scientific developments related to food chemistry was presented on the basis of visualisation (Kamdem et al., 2019), and the evolution of heat integration and heat exchanger network synthesis was studied by VoS viewer (Morar & Agachi, 2010). Up to now, some popular visualisation tools have been used to make science mapping analysis, such as VoS viewer (Stopar & Bartol, 2019), CiteSpace (Chen, 2006) and CitNetExplorer (Eck & Waltman, 2014). In this paper, VoS viewer and CiteSpace are chosen to make a comprehensive and deep analysis of the journal. On the one hand, VoS viewer can present the structure of publications in the journal by co-citation analysis, co-authorship analysis and co-occurrence analysis, etc. Scholars can grasp hot topics and track development trend of the journal by burst detection analysis and timeline analysis in CiteSpace. Since VoS and CiteSpace are convenient to use and produce images intuitively, they have been widely used in many areas, such as computer and information ethics (Heersmink et al., 2011), emergency medicine (Chan & Kuehl, 2019), and information literacy assessment (Pinto, 2015).
Economic Research-Ekonomska Istra zivanja is an international journal indexed in the Social Science Citation Index (SSCI) database with an impact factor of 1.381 by Journal Citation Reports (2018), and ranked 160 among 363 journals in the research field of business and economics. The journal supported by the ministry of science and education of the Republic of Croatia, and was launched in 2007. According to the homepage of the journal (https://www.tandfonline.com/toc/rero20/current), it publishes an issue per year, and publishes rigorous scientific papers which contribute significantly to any field of economics-theoretical, applied or empirical. At present, professor Marinko Skare from the Juraj Dobrila University of Pula is the editor of the journal. To date, Economic Research-Ekonomska Istra zivanja has published over 800 documents with the development of 13 years. Therefore, it is valuable to make a systematic and intuitive analysis of the journal based on bibliometric methods and visualisation tools.
According to general analysis and science mapping analysis, this paper makes a bibliometric analysis of Economic Research-Ekonomska Istra zivanja. For one thing, readers can evaluate the merits of the journal, and explore the publications' structure and the development trend of the journal. For another, researchers can see the internal network structure intuitively at level of countries/regions, institutions and authors, and grasp hot topics greatly of the journal over time. Since the first paper published in Economic Research-Ekonomska Istra zivanja in 2007 (Baldarelli et al., 2007), we analyse the journal from 2007 to 2019. In this paper, the contributions lie in the following aspects: (1) Characteristics of publications are provided to describe the development of the journal from three aspects, which are an annual analysis of publications, who is paying attention to the journal, and the most cited publications.
(2) Influential countries/regions and institutions of publications in the journal are presented based on some widely recognised bibliometric indictors, such as the total number of publications (TP), the total number of citations (TC), the average number of citations (AC), the percentage of TP (%TP), and H-index (Hirsch, 2005). (3) Science mapping analysis is given through VoS viewer and CiteSpace, including cocitation analysis at the level of reference/source/author, co-authorship analysis of countries/regions and authors, burst detection analysis of cited authors and cited journals, co-occurrence analysis and timeline view analysis of keywords. (4) The future challenges of Economic Research-Ekonomska Istra zivanja are discussed based on the above analysis. The rest of this paper is organised as follows: Section 2 illustrates the data source and bibliometric methods. In Section 3, we give some results including characteristics of publications, influential countries/regions and institutions, and science mapping analysis. Section 4 provides some discussions about future challenges in the research field. Section 5 ends the paper with the conclusions.

Data source and bibliometric methods
Since the first article was published in Economic Research-Ekonomska Istra zivanja in 2007, we make a bibliometric analysis of the journal from 2007 to 2019. We derived the data from the Web of Sciences (WoS) Core Collection database on December 31, 2019, using the name of the journal. WoS is one of the most widely used databases in academics (Falagas et al., 2008), which is owned by the company Thomson & Reuters Corporation, and provides many leading journals available and detailed information about publications around the world. All publications of the journal from 2007 to December 31, 2019, are exported in plain text format and Comma-Separated Values (CSV) format, which contains bibliographic information, keywords information and citation information, etc. As a result, 831 publications are derived and analysed to provide informative and representative perspectives of the data.
In this paper, some accepted bibliometric indicators by the scientific community are used to evaluate the research's influence and productivity. We use total number of publications (TP), total number of citations (TC), average number of citations per publication (AC), and H-index. In particular, H-index considers both the number of publications and citations, and it can be applied to authors, countries and institutions. Therefore, H-index without self-citations and the citations without self-citations are considered as two important indicators to express research quality. The rankings may be different because of the specific considered indicator, and scholars may interpret various results depending on their requirements or interests (Hsieh & Chang, 2009).
Two visualisation tools, i.e., CiteSpace and VoS viewer, are used to make science mapping analysis of publications in the journal, because they have powerful user graphic-interface and mapping visualisation capability. To be specific, co-citation analysis of references, sources and authors can identify a research field trend and measure the proximity degree. Co-authorship network analysis shows the number of publications co-authored by at least two countries/regions, institutions, or authors. Cooccurrence analysis of keyword terms represents the number of times that two terms occur together in a set of publications (Kamdem et al., 2019), and timeline analysis shows the developing tendency of the journal during the whole time period. The CiteSpace and the VoS viewer are freely available and are found at: http://cluster.ischool.drexel.edu/cchen/citespace/download/ and https://www.vosviewer.com/, respectively.

Results
According to the bibliometric analysis of the journal, some results are presented from three aspects, which are characteristics of publications, influential countries/regions and institutions, and science mapping analysis, respectively.

Characteristics of publications
In this subsection, we investigate characteristics of publications in Economic Research-Ekonomska Istra zivanja from three angles: annual analysis of publications, who is paying attention to the journal, and the most cited publications, respectively. Figure 1 gives the number of publications and the number of citations distribution in the journal from 2007 to 2019. In Figure 1a, the publication-year distribution shows an increasing trend. To be specific, the annual publication was less than 20 in the first five years from 2007. Since 2012, the number of publications has been increasing steadily, and the annual publications are greater than 100 from 2017 to 2019. The number of publications increased significantly in 2019, which shows that more and more researchers have paid attention to the journal. Figure 1b shows the citation-year distribution. The publications receive the most citations (489) in 2015, followed by 327 citations in 2017, and 308 citations in 2014. The trend of citations had been increasing from 2007 to 2015. Besides, the falloff of citations since 2017 does not imply that no excellent contributions appeared, but that it always needs time for publications to be widely recognised and cited (Pilkington & Meredith, 2009).

Annual analysis of publications
There are 4 types of publications in the journal during the last 13 years, shown in Figure 2 (a). Specifically, 803 articles with 96.631% occupies a comparatively great proportion of all publications, followed by 37 early access papers with 4%, 25 reviews with 3.008%, and 3 corrections with 0.361%. In terms We summarise the annual characteristics of publications in the journal from 2007 to 2019 in Table 1. Except for some common indicators, like TP, TC, AC and Hindex, other evaluation indicators are also used to describe the characteristics of publications, such as the number of non-international cooperation (NNIC), the number of international cooperation (NIC), the number of a single institution (NSI), the number of multiple institution cooperation (NMIC), the number of a single author (NSA) and the number of multiple authors (NMA). Some publications in WoS do not have the corresponding information about authors, such as affiliated addresses,  institutions and countries. In this paper, we ignore these publications when calculating NNIC, NIC, NSI and NMIC.
In Table 1, we highlight the maximum value of each indicator in bold. The most TP (257), the most TC (489), the most AC (7) and the most H-index (10) are in 2019, 2015, 2010 and 2014, respectively. Considering the situation of international cooperation, NNIC is always greater than NIC during each year, and the most NIC is in 2019, which shows that it is the trend to finish papers by international cooperation. As far as institution cooperation is concerned, NMIC has been greater than NSI since 2015, and the most NMIC is in 2019, which represents that the cooperation among institutions has received more and more attention in the journal. According to the number of authors, NMA has always been no less than NSA since 2007, and NMA has been substantially greater than NSA in many years. Figure 3 shows the change trends of six indicators, and the percentages of NIC, NMIC, and NMA. The development of publications in the journal is not stable in the first five years, while six indicators have presented overall increasing trends since 2012. Specifically, the percentage of NIC and the percentage of NMIC increased from  0% and 20% in 2007 to 22% and 58% in 2019 with fluctuations, respectively. Besides, over 80% publications in the journal are multiple authors since 2014. Therefore, the cooperation among countries/regions, institutions and authors in Economic Research-Ekonomska Istra zivanja has become increasingly remarkable and important.

Who is paying attention to the journal?
Economic Research-Ekonomska Istra zivanja is an international journal in business and economics. Many scholars have paid attention to the journal around the world. Considering countries/regions, institutions and authors, we make a summary to understand top 10 sources citing more publications in the journal, shown in Table 2.
In terms of countries/regions, the scholars in Croatia have cited the most publications (156) in Economic Research-Ekonomska Istra zivanja, followed by China (94), Slovenia (75) and Turkey (70), respectively. As far as an institution is concerned, University of Zagreb from Croatia cites 70 citing publications and it ranks the first, followed by the University of Ljubljana from Slovenia (42), Juraj Dobrila University of Pula from Croatia (40), and Vilnius Gediminas Technical University from Lithuania (37), respectively. In the top 10 institutions, six institutions are from Croatia, two institutions are from Slovenia, and Lithuania, respectively, and Serbia has one institution. On the author's side, Zavadskas, E. K. and Streimikiene, D. both from Lithuania rank the first and the second with 19 publications and 10 publications, respectively. Therefore, the publications in Economic Research-Ekonomska Istra zivanja have aroused special attention for scholars in Croatia, Lithuania and Slovenia.

The most cited publications
Since Economic Research-Ekonomska Istra zivanja published papers, some publications impact the field of business and economic. Table 3 shows the information of top 10 cited publications, including type, year, citation, CA, institution number (IN) and country/region number (CN).
In Table 3, 6 publications are articles and 4 publications are reviewed. The top 3 cited publications are all reviews (Mardani et al., 2015;Zavadskas et al., 2016;Keshavarz Ghorabaee et al., 2017), and the research contents are all about decision making, which has been widely studied from basic theory and practical application . The most cited publication is a review of the literature from 2000 to 2014 about multiple criteria decision-making techniques and their applications. Decision making is the part of real life, and it has played more and more important role under complex and uncertain environment. From the perspectives of economic prediction, economic decision may be a valuable research direction with higher mathematical theory to economic field. Besides, more than half of publications are multiple institutions and multiple countries/regions. Specifically, 4 publications have two institutions, and 3 publications have three and four institutions, respectively. 80% of highly cited publications are international cooperation. Therefore, the cooperation of institutions and countries/regions is important to make the highly cited publications.

Influential countries/regions and institutions
In this subsection, influential countries/regions and institutions about publications in Economic Research-Ekonomska Istra zivanja are obtained by some evaluation indicators, which are TP, TC, AC, the numbers of citations no less than 30/20/10/5, %TP, and H-index. Table 4 shows the top 10 productive countries/regions of publications in the journal, and they also highlight the maximum value of each indicator in bold. According to TP and %TP, Croatia ranks the first, followed by China and Slovenia. Lithuania is the most TC and the highest H-index country with 575 and 14, respectively, followed by Croatia (556; 10) and Slovenia (302; 9). Lithuania is also the most AC country with 10.45, and the numbers of citations no less than 30/20/15 all rank the first, which denotes that the publications in the journal from Lithuania have received the highest recognition. In terms of TP, TC, AC and H-index, the radar map of top 10 productive countries/regions is shown in Figure 4. As far as TP and TC are concerned in Figure 4a, Croatia and Lithuania are prominent, and the gap of TC is wider than the gap of TP among top 10 countries/regions. According to AC and H-index in Figure 4b, Lithuania both does well, and secondly are Croatia and Serbia. The structure of AC and H-index is similar among top 10 countries/regions.

The most productive countries/regions
We distribute the authors of publications in the journal around the world, and the global geographic distribution of publications covers about 68 countries/regions, shown in Figure 5. The redder the colour in the map, the more publications form the countries/regions. As we can see, the productive countries/regions are mainly from Europe and East Asia. Figure 6 presents the cumulative percentage of publications with top 30 countries/ regions, and the logarithmic trend line is y ¼ 0:2582 ln ðxÞ þ 0:0743 with R 2 ¼ 0:9862: To be specific, the publications in the journal from the top 10 countries/ regions have contributed to 68.81%, and the publications from the top 20 and the top 30 have contributed to 88% and 94.68%, respectively.

The most productive institutions
Similarly, we also investigate the most productive institutions among totally 665 institutions in the journal, and we list the information of top 10 productive institutions in Table 5. The University of Zagreb (Croatia) is the most productive institution in terms of TP and %TP, followed by the University of Ljubljana (Slovenia) and Juraj Dobrila University of Pula (Croatia). Six of the top 10 productive institutions are from Croatia, which shows that the institutions in Croatia have a strong interest in Economic Research-Ekonomska Istra zivanja. Vilnius Gediminas Technical University (Lithuania) is the most influential institution according to TC, AC, the numbers of citations no less than 30/20/10/5 and H-index, which represents that the publications of the institution in the journal have in-depth research and wide recognition. Figure 7 shows the radar map of the top 10 productive institutions. In Figure 7a, the number of TP has a little difference among top 10 institutions, while the gap is bigger about the number of TC, and Vilnius Gediminas Technical University   (Lithuania) performs well in terms of TC, followed by the University of Zagreb (Croatia). In Figure 7b, except for Vilnius Gediminas Technical University (Lithuania), there are a little difference about AC and H-index among other top 9 institutions.

Science mapping analysis
In this section, we make science mapping analysis of publications in Economic Research-Ekonomska Istra zivanja by VoS viewer and CiteSpace from four aspects, i.e., co-citation analysis, co-authorship analysis, burst detection analysis, and co-occurrence analysis and timeline view analysis.

Co-citation analysis
Considering the cited references/sources/authors by publications in Economic Research-Ekonomska Istra zivanja, co-citation networks are illustrated and analysed.  According to the visualisation tool VOS viewer, the reference co-citation network by publications is shown in Figure 8. We set the minimum number of citations as 10 to see. As a result, 26 references meet the threshold among totally 26,289 references. In Figure 8, a node shows a reference, and the size of the node means the total number of citations with which we cite the reference. A link between two nodes represents a co-citation relationship, and the thicker the link is, the more citations the reference has. The place of the nodes and the colours are used to cluster the items, and there are three clusters from the perspective of three colours. The top cited we label references with the first author, year and journal. Figure 9 shows the source and author co-citation networks by publications in the journal by CiteSpace. There are 10,934 nodes and 84,235 edges in Figure 9a, and 19,241 nodes and 117,824 edges in Figure 9b. The nodes represent the cited sources/authors by publications in the journal where the size and the colour of the node mean that the scope and the citation of the source/author. To be specific, the bigger the node is, the broader the source/author is, and the deeper the colour is, the more citations the source/author has. Therefore, some large-sized nodes highlighted in Figure 9 mean the top cited sources/authors by publications in Economic Research-Ekonomska Istra zivanja. Table 6 lists the information of top 10 cited references/sources/authors by publications in the journal. More than half of top 10 references are before 2000, and the first

Co-authorship analysis
To describe the collaboration relationship of publications in Economic Research-Ekonomska Istra zivanja from 2007 to 2019, we make co-authorship analysis by VoS viewer at the level of country/region and author.
When the minimum numbers of publications and citations are 1 and 0, respectively, there are 68 countries/regions of publications in the journal, and the co-authorship network of countries/regions is shown in Figure 10. According to various colours, there are totally 11 clusters, and the most prominent countries of each cluster are Croatia, Turkey, Serbia, China, Romania, Lithuania, Pakistan, Spain, Iran, Malaysia and Egypt, respectively. Besides, countries/regions in same colour show that they are in the same cluster and may have more cooperation with each other. For example, Croatia, Slovenia and Poland prefer to cooperate each other in blue cluster, and China, England and Taiwan have more cooperation in red cluster.
Similarly, the minimum numbers of publications and citations are also set as 1 and 0, respectively, 1,462 authors of publications in the journal are derived. Figure 11 shows the co-authorship network of authors, and there are 10 clusters because of ten colours. As we can see, some authors interweave with each other, and Zavadskas, E. In addition, more than half of prominent authors are from Lithuania, which shows that the authors from Lithuania have made great contributions to Economic Research-Ekonomska Istra zivanja.

Burst detection analysis
To reflect the dynamic changes and the surging frequency of citations of publications in Economic Research-Ekonomska Istra zivanja during a certain period, citation burst detection analysis is used to reflect the emerging trends that attracted attention by the academic.     3 years, which shows that their work has made a far-reaching impact. Besides, the citation bursts of four authors (NARAYAN P.K., LEE C.C., SHAHBAZ M. and JENSEN M.C.) are the closest to the present (from 2017 to 2019), which represents that their work may have formed a popular and hot topic.
Similarly, Table 8 lists the top 10 cited journals with the strongest citation bursts from 2007 to 2019. J. MONEY CREDIT BANK has the strongest strength with the value of 6.0297. It is a primary economics journal reporting major findings in the study of monetary and fiscal policy, credit markets, money and banking, portfolio management, and related subjects. The citation burst of the cited journal of MANAGE DECIS had the longest duration with 7 years from 2010 to 2016. J. MARKETING started the earliest from 2008, which illustrates that the publications in Economic Research-Ekonomska Istra zivanja cited it earlier and explosively.

Co-occurrence analysis and timeline view analysis
To understand the research topics of publications in Economic Research-Ekonomska Istra zivanja, co-occurrence analysis of keywords is an effective and important tool to support knowledge mining and provide a view of the knowledge structure and research trend.
There are 3,594 keywords of publications in the journal from 2007 to 2019 using VoS viewer, and 197 keywords meet the threshold that we set the minimum number of occurrences of a keyword as 5. Figure 12 shows the keyword co-occurrence network of publications. A node represents a keyword, and the bigger the node is, the more citations the keyword has. A link between two nodes means the co-occurrence of two keywords, and the thicker the line is, the more co-occurred times they have. Similarly, a colour represents a cluster, and there are 6 clusters in Figure 12. To be specific, 'performance', 'impact' and 'innovation' are prominent in red cluster; 'management', 'selection' and 'efficiency' highlight in purple cluster; 'Croatia', 'cointegration' and 'panel-data' are included in green cluster; 'market' and 'risk' are labelled in blue cluster; 'economic growth' and 'growth' are prominent in yellow cluster; 'models' and 'education' are included in light blue cluster. Figure 13 shows the keyword clusters visualisations by CiteSpace. 9 clusters are summarised among all keywords of publications in Economic Research-Ekonomska Istra zivanja, which are 'EU', 'loyalty', 'ambidexterity', 'value creation', 'economic growth', 'financial performance', 'information and communication technology', 'Croatia' and 'Romania' in order.

Discussion
Economic Research-Ekonomska Istra zivanja explores broad economic topics that can contribute to the development of economics. After the bibliometric analysis, we have further discussed the possible reasons and given the future suggestions.
According to general analysis of the journal, the publications' structure and the development trend are explored. The characteristics of publications, productive countries/regions and productive institutions are summarised as follows: 1. The publication-year distribution shows an increasing trend from 2007 to 2019, the reason may be that the journal has been developed, and more and more researchers pay attention to it. The trend of citations had been increasing from 2007 to 2015, and publications received the most citations (489) in 2015, which indicates that the journal has gained more and more recognition. 2. The most type of publications is article, and occupies 96.631%. There are more high-quality publications in 2010 and 2014 because of highest AC and H-index, respectively. 3. In terms of evaluation indicators, it is the trend that the highly cited publication is cooperative. Because communication and cooperation are a good way to improve the quality of publication, and the cooperation has become increasingly remarkable and important among countries/regions, institutions and authors. 4. Since the top 3 cited publications are related to decision making, it is a hot and important research direction. The reason may be that decision making has been widely studied from both basic theory and practical application. 5. Publications cover about 68 countries/regions, and the productive countries/ regions are mainly from Europe and East Asia. In terms of TP, TC, AC and Hindex, Lithuania and Croatia are prominent, which shows that publications in the journal from these two countries have higher influence. 6. Six of the top 10 productive institutions are from Croatia, which shows that the institutions in Croatia have a strong interest in the journal. University of Zagreb (Croatia) is the most productive institution, and Vilnius Gediminas Technical University (Lithuania) is the most influential institution. Therefore, the journal has aroused special attention for scholars in Croatia and Lithuania.
According to science mapping analysis of the journal, the internal network structures and hot topics are presented intuitively in the following aspects: 1. Considering the cited references/sources of publications in the journal, the results of co-citation networks show that the top 10 cited references are from 1979 to 2002 without significant TC, which indicates that publications cite references universally. The top 10 cited sources are all economic or management journals, and researchers can focus on publications in these journals. 2. Co-authorship analysis shows cooperative countries/regions and authors. The results present that partnerships between countries/regions are relatively fixed and limited. Zavadskas, E. K. (Lithuania) performs well about cooperation, and more than half of prominent authors are from Lithuania. Therefore, transnational cooperation can be further increased for high-quality publications in the future. 3. Burst detection analysis reflects the emerging trends that attracted attention during a certain period. According to the results of citation bursts, researchers can pay more attention to those authors (NARAYAN P.K., LEE C.C., SHAHBAZ M. and JENSEN M.C.) and journals (J. MONEY CREDIT BANK and MANAGE DECIS.). 4. Co-occurrence analysis and timeline view analysis show the knowledge structure and research trends in the journal. According to the results, the following research topics can be considered in the future: (a) To study monetary policy of a country/region taking into account multiple factors, such as inflation, interest rates and exchange rate, combined with panel-data, granger causality and autoregressive time series method. (b) To study economic growth of a country/region considering GDP, globalisation economic crisis, investment and CO 2 emissions. (c) To study a corporation's stock returns taking risks in drastic competition under uncertain market environment. (d) To study the poverty and education of a country/region based on models. (e) To study industry orientation and sustainable development based on network data envelopment analysis, analytic hierarchy Overall, the paper provides an aim view of Economic Research-Ekonomska Istra zivanja by bibliometric analysis, which is an essential and valuable tool for scholars to understand the trend and grasp some hot topics of a journal or a research direction.