1. Age Wave. (1989). The shifting American marketplace. Age Wave.
2. Belsky, J. K. (1984). The psychology of aging: Theory, research, and practice. Wadswort publishing.
3. Birren, J. E., & Schaie, K. W. (1985). Handbook of the psychology of aging (2nd ed.). Van Nostrand Reinhold.
4. Buglass, K. (1989, October). The business of eldercare. American Demographics 32–38.
5. Carmeli, E., Patish, H., & Coleman, R. (2003). The aging hand. Journal of Gerontology, 58A(2), 146–152.