Existing winter use management guidelines, inventory, and needs :
Yellowstone National Park.
APA Citation
United States. National Park Service. (1989). Existing winter use management guidelines, inventory, and needs: Yellowstone National Park. [Washington, D.C.?: U.S. Dept. of the Interior, National Park Service.
MLA Citation
United States. National Park Service. Existing Winter Use Management Guidelines, Inventory, And Needs: Yellowstone National Park. [Washington, D.C.?: U.S. Dept. of the Interior, National Park Service, 1989.
Warning: These citations may not always be complete (especially for serials).