Dyfyniad APA

Field, B. C., & Field, M. K. (2006). Environmental economics: An introduction (4th ed.). McGraw-Hill/Irwin.

Dyfyniad Arddull Chicago

Field, Barry C., and Martha K. Field. Environmental Economics: An Introduction. 4th ed. New York, New York: McGraw-Hill/Irwin, 2006.

Dyfyniad MLA

Field, Barry C., and Martha K. Field. Environmental Economics: An Introduction. 4th ed. McGraw-Hill/Irwin, 2006.

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