Bustad, L. K. (1980). Animals, aging, and the aged. University of Minnesota Press.
Lua i Stíl Chicago (17ú heag.)Bustad, Leo K. Animals, Aging, and the Aged. Minneapolis: University of Minnesota Press, 1980.
Lua MLA (9ú heag.)Bustad, Leo K. Animals, Aging, and the Aged. University of Minnesota Press, 1980.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.