A collection that includes the major published source materials required for dissertation and independent research, including materials containing research reporting, new findings, scientific experimental results, and other information useful to researchers. It is intended to include all important reference works and a wide selection of specialized monographs, as well as a very extensive collection of journals and major indexing and abstracting services in the field. Pertinent foreign language materials are included. Older material is usually retained for historical research and actively preserved. A collection at this level supports doctoral and other original research.
Older material is retained for historical research with active preservation efforts.