Dyfyniad APA

Field, B. C. (1997). Environmental economics: An introduction (2nd ed.). McGraw-Hill.

Dyfyniad Arddull Chicago

Field, Barry C. Environmental Economics: An Introduction. 2nd ed. New York: McGraw-Hill, 1997.

Dyfyniad MLA

Field, Barry C. Environmental Economics: An Introduction. 2nd ed. McGraw-Hill, 1997.

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