Dyfyniad APA

Thomas, J. M., & Callan,Scott. (2009). Environmental economics (India ed.). Cengage Learning.

Dyfyniad Arddull Chicago

Thomas, Janet M., and Callan,Scott. Environmental Economics. India ed. New Dehli: Cengage Learning, 2009.

Dyfyniad MLA

Thomas, Janet M., and Callan,Scott. Environmental Economics. India ed. Cengage Learning, 2009.

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