Dyfyniad APA

rolston, H. Conserving natural value. columbia university press.

Dyfyniad Arddull Chicago

rolston, Holmes. Conserving Natural Value. New York: columbia university press.

Dyfyniad MLA

rolston, Holmes. Conserving Natural Value. columbia university press.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.