Dyfyniad APA

Perman, R., Ma, Y., Common, M., Maddison, D., & McGlivray, J. (2011). Natural resource and environmental economics (Forth edition.). Pearson Addison Wesley.

Dyfyniad Arddull Chicago

Perman, Roger, Yue Ma, Michael Common, David Maddison, and James McGlivray. Natural Resource and Environmental Economics. Forth edition. Harlow, Essex ; New York: Pearson Addison Wesley, 2011.

Dyfyniad MLA

Perman, Roger, et al. Natural Resource and Environmental Economics. Forth edition. Pearson Addison Wesley, 2011.

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