1. Approval Plans—Bounty or Bedlam?;DeVolder;Publishers Weekly,1972
2. Selecting an Approval Plan Vendor: A Step-by-Step Process;Reidelbach;Library Acquisitions: Practice and Theory,1983
3. Special Emphasis Acquisitions Plans;Biblarz,1980
4. Waiting for Godot: Rating Approval Service Vendors;Mosher,1980
5. Frye Gloria. Letter to Gary M. Shirk, dated November 11, 1983.