Keeton, W. T. (1972). Elements of biological science (2nd ed.). W.W. Norton.
Chicago-čujuhus (17. p.)Keeton, William T. Elements of Biological Science. 2nd ed. New York: W.W. Norton, 1972.
MLA-čujuhus (9. p.)Keeton, William T. Elements of Biological Science. 2nd ed. W.W. Norton, 1972.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.