Cita APA (7th ed.)

Willis, K. G., Button, K., & Nijkamp, P. (1999). Environmental valuation. Edward Elgar Pub. Ltd.

Cita Chicago (17th ed.)

Willis, Kenneth G., Kenneth Button, i Peter Nijkamp. Environmental Valuation. Cheltenham, U.K: Edward Elgar Pub. Ltd, 1999.

Cita MLA (9th ed.)

Willis, Kenneth G., et al. Environmental Valuation. Edward Elgar Pub. Ltd, 1999.