White, Howard D.; Griffith, Belver C. (1981). "Author Cocitation: A Literature Measure of Intellectual Structure". Journal of the American Society for Information Science. 32 (3): 163–171. doi:10.1002/asi.4630320302.
Class Amsler written by Bruno Martins and developed by the XLDB group of the Department of Informatics of the Faculty of Sciences of the University of Lisbon in Portugal
See for example "Multiple Independent Discovery and Creativity in Science," Current Contents, Nov. 3, 1980, pp. 5-10, reprinted in Essays of an Information Scientist, vol. 4 (1979-80), pp. 660-665.