Lynch, Tim . 2006. Helicopter Rappel. 0651 2W02. Missoula, MT: U.S. Department of Agriculture, Forest Service, Missoula Technology and Development Center.
This Web site contains information on types of rappel equipment, cargo letdown equipment, and rappel anchors, as well as procurement sources for each piece of equipment. The site also contains rappel-related PowerPoint presentations and bulletins.