4) Steven, R. G, Susan, L., Kelley: Relationsip in very elderly veterans of nutritional status, self-perceived ability, dental status, and social isolation, J. Am. Geriat. Soc. 33 (5): 334-339, 1985.
5) Reisine, S., T., Fertig, J., Weber, J., Leder, S., : Impact of dental conditions on patients' quality of life, Comunity Dent. Oral Epidemiol., 17: 7-10, 1989.