The variable" loan and duplication policy which was developed is described and also the considerable impact of implementation. The work is presented as a case study in library O.R. The great importance of analyzing the structure of problems is stressed and the nature and usefulness of models is described. (9 references) (Author/NH)

This article focuses on storage models for libraries, first considering the Dewey classification system from this perspective and then summarizing more current research carried out under the direction of the author with a grant from the National Science Foundation. (33 references) (Author/NH)