The distribution of bibliographic records in databases using different counting methods for duplicate records

Knowing how records on a particular topic are distributed over databases is useful for both practical and theoretical reasons; however little work in this area appears to have been done. This paper examines the distribution o f records on the topic of "Fuzzy Set Theory" in over 100 bibliographic data bases and determines whether the distribution of records over databases is similar to the traditional Bradford hyperbolic distribution of records over journals. Different methods for counting duplicate records between and wit hin databases have been developed. A comparison of the various distribution s based on these counting methods is presented; and the distributions are c ompared to results of earlier studies. The results also give an indication of the number of databases necessary to search for coverage of a literature to specified percentages using the different counting techniques developed in this study.