Calhoun, J. B. (1983). Environment and population: Problems of adaptation. Praeger.
Lua i Stíl Chicago (17ú heag.)Calhoun, John B. Environment and Population: Problems of Adaptation. New York: Praeger, 1983.
Lua MLA (9ú heag.)Calhoun, John B. Environment and Population: Problems of Adaptation. Praeger, 1983.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.