Dyfyniad APA

Botkin, D. B., & Keller, E. A. (2011). Environmental science: Earth as a living planet (8th ed.). Wiley.

Dyfyniad Arddull Chicago

Botkin, Daniel B., and Edward A. Keller. Environmental Science: Earth as a Living Planet. 8th ed. Hoboken, N.J: Wiley, 2011.

Dyfyniad MLA

Botkin, Daniel B., and Edward A. Keller. Environmental Science: Earth as a Living Planet. 8th ed. Wiley, 2011.

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