1. “Reference Collection Development in Academic Libraries: Report of a Survey”;Biggs;RQ,1987
2. “Reference Service in the Digital Age: An Analysis of Sources Used to Answer Reference Questions”;Bradford;Journal of Academic Librarianship,2005
3. “Weeding of Academic Library Reference Collections: A Survey of Current Practice”;Engeldinger;RQ,1986
4. Ibid., p. 371.
5. “‘Use’ as a Criterion for the Weeding of Reference Collections: A Review and Case Study”;Engeldinger,1990