Enger, E. D., & Smith, B. F. (1992). Environmental science: A study of interrelationships (4th ed.). W.C. Brown.
Lua i Stíl Chicago (17ú heag.)Enger, Eldon D., agus Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. 4th ed. Dubuque, IA: W.C. Brown, 1992.
Lua MLA (9ú heag.)Enger, Eldon D., agus Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. 4th ed. W.C. Brown, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.