Enger, E. D., & Smith, B. F. (2004). Environmental science: A study of interrelationships (Ninth edition.). McGraw-Hill Higher Education.
Chicago-referens (17:e uppl.)Enger, Eldon D., och Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. Ninth edition. Boston: McGraw-Hill Higher Education, 2004.
MLA-referens (8:e uppl.)Enger, Eldon D., och Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. Ninth edition. McGraw-Hill Higher Education, 2004.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.