Freeman, A. M. (2003). The measurement of environmental and resource values: Theory and methods (2nd ed.). Resources for the Future.
Lua i Stíl Chicago (17ú heag.)Freeman, A. Myrick. The Measurement of Environmental and Resource Values: Theory and Methods. 2nd ed. Washington, DC: Resources for the Future, 2003.
Lua MLA (8ú heag.)Freeman, A. Myrick. The Measurement of Environmental and Resource Values: Theory and Methods. 2nd ed. Resources for the Future, 2003.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.