BorzoneJ., Safety in Outdoor Recreation Activities.Washington D.C.: American Alliance for Health, Physical Education, Recreation and Dance, 1977.
2.
KudlasJ., The Rock Climbing Teaching Guide.Washington D.C.: American Alliance for Health, Physical Education, Recreation and Dance, 1979.
3.
McEwanDouglas, and McGinnisMichael, Recreationists in High Bluff Environs of Giant City State Park. Report on file in Department of Recreation, Southern Illinois University, Carbondale, Illinois.