Dyfyniad APA

Botkin, D. B., & Keller, E. A. (2007). Environmental science: Earth as a living planet (6th ed.). Wiley.

Dyfyniad Arddull Chicago

Botkin, Daniel B., and Edward A. Keller. Environmental Science: Earth as a Living Planet. 6th ed. Hoboken, NJ ; New Delhi: Wiley, 2007.

Dyfyniad MLA

Botkin, Daniel B., and Edward A. Keller. Environmental Science: Earth as a Living Planet. 6th ed. Wiley, 2007.

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