Schubert András, Zsindely Sándor, Glänzel Wolfgang, Braun Tibor (szerk.): A tudományos publikációs tevékenység mutatószámai az MTA természettudományi, műszaki, orvostudományi és agrártudományi kutatóhelyein 1976–1980 (A MTAK Informatikai És Tudományelemzési Sorozata 2., 1982)

VII. FÜGGELÉK - 2. A „Journal Citation Reports" által nyilvántartott folyóiratok „impact factorai"

105 munications, letters to the editor, editorials, etc.; in other words, individual items published in journals. An article cited three times in the references of the same SC7*source item is counted as having been cited by that source item once. Thus, 'times cited' in the case of articles is the cumulative number of times the article has been cited once or more by single source items. In the case of articles, therefore, 'times cited' is equivalent to the number of source items that have cited the article. Times Cited: Books and Other 'Non-JoumaT Items. The references of journal items contain citations of many different types of publications. About 80% of the references cite other journal items. The remaining 20% cite books (single- or multi-authored monographs); edited collections of single- or multi-authored 'contributions' or 'chapters' or 'sections'; variously compiled and formatted collations of reports and papers produced by meetings, symposia, congresses; technical reports of academic, industrial, and governmental origin; personal communications; items in press; theses; 'unpublished' reports; collected works of classical and modern authors; hand-books, textbooks, data compilations; encyclopedias and other reference works; etc. A great deal of such material presents problems for citation analysis that the journal article does not. First, styles of citation vary widely and wildly. Second, internal citation (of a single page, series of pages, section, chapter, etc.) is particularly frequent. Third, different revisions or editions, by the same authoris) or by the same or different editor(s), may be cited. "Non-journal" items cited more than once in the references of the same source item are subject to certain ISI® conventions. For example, if a book is cited identically several times or if the only differences in its citations are page and chapter numbers, the book is counted as having been cited once. However, if two (or more) editions or revisions of the book are cited, the book is counted as having been cited two (or more) times.