rolston, H. Conserving natural value. columbia university press.
Chicago-čujuhus (17. p.)rolston, Holmes. Conserving Natural Value. New York: columbia university press.
MLA-čujuhus (9. p.)rolston, Holmes. Conserving Natural Value. columbia university press.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.