APA-referens (7:e uppl.)

Wills, I. R. (2007). Economics and the environment: A signalling and incentives approach (2nd ed.). Allen & Unwin.

Chicago-referens (17:e uppl.)

Wills, Ian R. Economics and the Environment: A Signalling and Incentives Approach. 2nd ed. St. Leonards, NSW: Allen & Unwin, 2007.

MLA-referens (8:e uppl.)

Wills, Ian R. Economics and the Environment: A Signalling and Incentives Approach. 2nd ed. Allen & Unwin, 2007.