1. 1 . Cooper KH: Aerobics. New York M. Evans &Co Inc. 1968.
2. 2. Hay flick L: The cellular basis for biological aging in Finch CE Hayflick L (eds): The Biology of Aging. New York Van Nostrand Reinhold Co 1977.
3. 3. Smith EL Serfass RC (eds): Exercise and Aging: The Scientific Basis. Hillside NJ EnslowPubs Ine 1981.
4. 4. Sorensen KC Luckmann J: Basic Nursing. Philadelphia W.B. Saunders Co 1979.
5. 5. Shephard RJ: Physical Activity and Aging. Chicago Year Book Medical Pubs Inc. 1978.