Network Analysis of Works on Clustering and Classification from Web of Science Nataˇ sa Kejˇ zar 1 , Simona Korenjak ˇ Cerne 2 , and Vladimir Batagelj 3 1 University of Ljubljana, Faculty of Social Sciences, Kardeljeva pl. 5, 1000 Ljubljana, Slovenia natasa.kejzar@fdv.uni-lj.si 2 University of Ljubljana, Faculty of Economics, Kardeljeva pl. 17, 1000 Ljubljana, Slovenia simona.cerne@ef.uni-lj.si 3 University of Ljubljana, Faculty of Mathematics and Physics, Jadranska 19, 1000 Ljubljana, Slovenia vladimir.batagelj@fmf.uni-lj.si Summary. Web of Science (WoS) is a database that provides information about current and past articles published in over 10,000 of the most prestigious, high im- pact research journals in the world from year 1970 on. A file with full information – records about selected articles – can be downloaded and further analyzed. We col- lected from WoS complete records on articles from Journal of Classification, articles citing these articles, and articles in WoS cited by them at least 10 times. A special program WoS2Pajek was developed for converting such data into Pajek network files. The citation network between articles, networks of articles × authors, articles × keywords, articles × journals, and the partition according to publication year were obtained from the data. These networks were analyzed in order to identify the most important authors, works and topics that have been involved in the field in the last decades. Key words: Network Analysis, Classification Society, Journal of Classification, bib- liographic data, Web of Science. 1 Introduction Web of Science (WoS) [19] is an online academic service provided by Thomson Reuters. It provides access to seven world’s leading citation databases: Science Citation Index, Social Sciences Citation Index, Arts & Humanities Citation Index, Index Chemicus, Current Chemical Reactions, Conference Proceedings Citation Index: Science, and Conference Proceedings Citation Index: Social Science and Humanities. It covers data on over 10,000 of the highest impact journals of science, technology, social sciences, arts, and humanities, and over 110,000 books and conference proceedings. WoS allows one to get full information, a record, about an article, a book or other work: its title, authors, abstract, keywords, publication properties