Harris, A., Harrison, C., & Smithson, P. (1972). The land and conservation. Grosset and Dunlap.
Lua i Stíl Chicago (17ú heag.)Harris, Anne, Carolyn Harrison, agus Peter Smithson. The Land and Conservation. New York: Grosset and Dunlap, 1972.
Lua MLA (9ú heag.)Harris, Anne, et al. The Land and Conservation. Grosset and Dunlap, 1972.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.