1. Images of Old Age in America, 1790 to the Present;Achenbaum,1978
2. Theoretical concepts governing gerontological research;Baker,1991
3. The Biology of Senescence;Comfort,1979
4. Problems of Aging,1939
5. Aging at the molecular level and some speculations concerning maintaining the functioning of systems for replicating specific mancomolecules;Medvedev,1962