Dyfyniad APA

Hartwick, J. M., & Olewiler, N. D. (1998). The economics of natural resources use (2a. ed.). Addison-Wesley.

Dyfyniad Arddull Chicago

Hartwick, John M., and Nancy D. Olewiler. The Economics of Natural Resources Use. 2a. ed. Reading: Addison-Wesley, 1998.

Dyfyniad MLA

Hartwick, John M., and Nancy D. Olewiler. The Economics of Natural Resources Use. 2a. ed. Addison-Wesley, 1998.

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