ebrary, Inc, Mangen, D. J., & Peterson, W. A. (1984). Research instruments in social gerontology. University of Minnesota Press.
Lua i Stíl Chicago (17ú heag.)ebrary, Inc, David J. Mangen, agus Warren A. Peterson. Research Instruments in Social Gerontology. Minneapolis, MN: University of Minnesota Press, 1984.
Lua MLA (9ú heag.)ebrary, Inc, et al. Research Instruments in Social Gerontology. University of Minnesota Press, 1984.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.