.Conrad, J. M., & .Clark, C. W. (1987). Natural resource economics: Notes and problems. Cambridge University Press.
Lua i Stíl Chicago (17ú heag.).Conrad, Jon M., agus Colin W. .Clark. Natural Resource Economics: Notes and Problems. [Cambridge [Cambridgeshire ; New York: Cambridge University Press, 1987.
Lua MLA (9ú heag.).Conrad, Jon M., agus Colin W. .Clark. Natural Resource Economics: Notes and Problems. Cambridge University Press, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.