4Bradford S. C. Sources of information on specific subject[J]. En- gineering, 1934, 137(3550):85-86.
5Garfield, E. The mystery of the transposed journal lists where in Bradford's Law of scattering is generalized according to Garfield's Law of concentration [J]. Current Contents, 1971 (17) :222-223.
6Garfield, E. The significant scientific literature appears in a small core of journals[J]. The Scientist Research, 1996, 10(17):13 -15.
7Richard L. Trueswe[[. Some behavuria[ patterns of |ihrary users,. The 80/20 rule[J], Wilson Library Bulletin, 1969,43(1):458 -461.