Dyfyniad APA

Botkin, D. B., & Keller, E. A. (2014). Environmental science: Earth as a living planet (9th ed.). Wiley.

Dyfyniad Arddull Chicago

Botkin, Daniel B., and Edward A. Keller. Environmental Science: Earth as a Living Planet. 9th ed. New Jersey: Wiley, 2014.

Dyfyniad MLA

Botkin, Daniel B., and Edward A. Keller. Environmental Science: Earth as a Living Planet. 9th ed. Wiley, 2014.

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