1. Behnke JA, Finch CE, Moment CB. The biology of aging. New York, Plenum Press, 1978.
2. Brocklehurst JC. (Editor) Textbook of geriatric medicine and gerontology, 2nd Ed. Edinburgh, Churchill Livingstone, 1978.
3. Powers JH. (Editor) Surgery of the aged and debilitated patient. Philadelphia, Saunders Co., 1968.
4. Rai GS, Pearce V. Databook on geriatrics, Lancaster MTP Press Ltd., 1980.
5. Djokovic JL, Hedley-Whyte J. Prediction of outcome of surgery and anaesthesia in patients over 80. JAMA, 1979; 242: 2301.