APA

Dixon J. A., Sherman P. B. & Dixon J. A. (1990). Economics of protected areas. Washington, DC [u.a.]: Island Press.

Chicago

Dixon John A, Sherman Paul B and Dixon John Alexander. 1990. Economics of protected areas. Washington, DC [u.a.]: Island Press.

Harvard

Dixon J. A., Sherman P. B. and Dixon J. A. (1990). Economics of protected areas. Washington, DC [u.a.]: Island Press.

MLA

Dixon John A, Sherman Paul B and Dixon John Alexander. Economics of protected areas. Washington, DC [u.a.]: Island Press. 1990.