1. National Science Board (NSF):Science Indicators 19xy; Government Printing Office, Washington D. C.
2. RAWB: Wetenschaps- en technologie-indicatoren: Een vergelijking van Nederland met buitenland op basis van kwantitatieve gegevens; Achtergrondstudies RAWB Nr, 11, Den Haag, 1984.
3. Database produced by the Institute for Scientific Information, Inc. Philadelphia, best known as publisher of theScience Citation Index (SCI).
4. E. GARFIELDCitation Indexing Chap. 8; John Wiley & Sons, New York, 1979.
5. E. GARFIELD, M. W. MALIN, H. SMALL, Chap. 8,Citation Data as Science Indicators; Toward a Metric of Science, Y. ELKANA et al. Ed.; John Wiley & Sons, New York, 1978.