Dyfyniad APA

Enger, E. D., & Smith, B. F. (2013). Environmental science: A study of interrelationships (13th edition.). McGraw Hill.

Dyfyniad Arddull Chicago

Enger, Eldon D., and Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. 13th edition. New York: McGraw Hill, 2013.

Dyfyniad MLA

Enger, Eldon D., and Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. 13th edition. McGraw Hill, 2013.

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