6D. Price, Little Science Big Science, New york, Colombia University Pree. 1963 ,pp. 82-89.
7A. J. Meadows, Scientific collaboration and status, In:Communication in Science,London,Butterworths, 1974,pp. 172-206.
8W. Glanzel, H. J. Czerwon, A new methodlogical approach to biblographic coupline and its application to national, regional and institutional oevel, Scientometrics,1996(2), 195-221.