1. de Lange, C., Glänzel, W., 1996. A Bibliometric Study on the Extent of Multilateral Co-authorship Links in International Scientific Collaboration. Paper presented at EASST/4S conference in Bielefeld, 1996.
2. Collaboration in an invisible college;de Solla Price;American Psychologist,1966
3. Glaser, B.G., Strauss, A.L., 1967. The Discovery of Grounded Theory; Strategies for Qualitative Research. Aldine Publ., Chicago.
4. Where is science going?;Hicks;Science, Technology and Human Values,1996
5. What is research collaboration?;Katz;Research Policy,1997