THE BRADFORD DISTRIBUTION THEORY: THE COMPOUNDING OF BRADFORD PERIODICAL LITERATURES IN GEOGRAPHY

World periodical literature output in geography from 1970 to 1973 and the output concerning the USA, British Isles, France, and Germany for the same period are presented in three sets of Bradford‐Zipf bibliographs, while the verbal formulation of the law is translated into seven tables based on the same data. Results suggest that the convolution of correlated and uncorrelated Bradford distributions yields another Bradford distribution and that data conforming with the verbal formulation of Bradford's law do not automatically conform with the linear ideal of a Bradford bibliograph and vice versa.