1. For a recent overview see:R.R. Braam,Mapping of Science: Foci of Interest in Scientific Literature, Thesis, DSWO Press, Leiden, 1991.
2. H.G. Small, B.C. Griffith: The structure of scientific literatures I: Identifying and graphing specialties,Science Studies, 4 (1974) 17–40.
3. M. Callon, J.P. Courtial, W.A. Turner, S. Bauin: From translations to problematic networks: An Introduction to Co-word Analysis,Social Science Information, 22 (1983) 191–235.
4. R.J.W. Tijssen, T.N. Van Leeuwen, A.F.J. Van Raan: Energy Research in the Netherlands in a Broad Perspective (1984–1989): An Explanatory Study Based on Bibliometric Data. Part I: Publication Output, International visibility, Interdisciplinarity. Research Report for the Ministry of Education and Science, CWTS-89-01, Centre for Science and Technology Studies, Leiden, 1989.
5. E. Noma:Subject Classification and Influence Weights for 3,000 Journals, Computer Horizons Inc., Cherry Hill NJ, 1986.