Dyfyniad APA

Enger, E. D., & Smith, B. F. (2013). Environmental science: A study of interrelationships (Thirteenth edition.). McGraw-Hill.

Dyfyniad Arddull Chicago

Enger, Eldon D., and Bradley F. Smith. Environmental Science: A Study of Interrelationships. Thirteenth edition. New York, NY: McGraw-Hill, 2013.

Dyfyniad MLA

Enger, Eldon D., and Bradley F. Smith. Environmental Science: A Study of Interrelationships. Thirteenth edition. McGraw-Hill, 2013.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.