1. Aspects of Medical Care Administration: Specifying Requirements for Health Care;Donabedian,1973
2. Expected medical emergencies an index of need for a region;Gurfield;JACEP,1977
3. University Michigan Certificate of Need for Helicopter Service, 1982.
4. 1980 Census of Population,1982
5. Lifeline: A physician staffed, helicopter-medicated emergency services in Indiana;Cordell;J Indiana State Med Assoc,1980