3Lum, T. Y. and Lighffoot,E. (2005) The Effects of Volunteering on the Physical and Mental Health of Older People. Research on Aging,27 (1) :31 -35.
4Greenfield, E. A. and Marks, N. F. ( 2004 ) Formal Volunteering as a Protective Factor for Older Adults' Psychological Well - being. The Journals of Gerontology Series B ,59 ( 5 ) : S258 - 264.
5Musiek M. A, Wilson J. (2003) Volunteering and depression : the role of psychological and social resources in different age groups [ J ]. Social Science and Medicine,56 : 259 - 269.
6Harlow, R. and Cantor, N. ( 1996 ) Still participating after all theseyears : A Study of Life Task Participation in Later Life. Journal of Person- ality and Social Psychology,71 (6) :1235 -1249.
7Thoits P. A, Hewitt L. N. (200!)Volunteer work and well -being [ J ]. Journal of ttealth and Sial Behavior.42 : 115 - 131.
8Rook,K. S. , Sorkin, D. H. (2003). Fostering social ties through a volunteer role : Implication for older - adults' psychological health. Inter- national Journal of Aging and Human Development,57 ( 4 ), 313 - 337.
