This report presents the results of a study of the nature and extent of overlap in coverage by the "Bibliography of Agriculture" (B of A) and 15 other abstracting and indexing services. Using a sample of over 5000 citations from 1967 issues of B of A, literature searches were made in 15 other related services to determine the extent and nature of overlapping coverage. One of the major findings was that approximately 54 percent of the B of A citations were not covered by any of these 15 other services. The material covered uniquely by B of A was not significantly different in national or linguistic origin or form of publication from the B of A material that was overlapped by the other services. A total of 156 different combinations of overlapping coverage were noted. The greatest amount of overlap was provided by "Pesticides Documentation Bulletin,""Biological Abstracts,""Chemical Abstracts,""Biological and Agricultural Index," in that order, with no single service overlapping more than 20 percent of the B of A data base. (Author)