Cita APA (7a ed.)

Ward, F. A., & Beal, D. J. (2000). Valuing nature with travel cost models: A manual. Edward Elgar.

Cita Chicago Style (17a ed.)

Ward, Frank A., y Diana J. Beal. Valuing Nature with Travel Cost Models: A Manual. Cheltenham [etc.]: Edward Elgar, 2000.

Cita MLA (9a ed.)

Ward, Frank A., y Diana J. Beal. Valuing Nature with Travel Cost Models: A Manual. Edward Elgar, 2000.