Cita APA (7th ed.)

KEETON, W. T. (1980). Biological science.-- ed.3. W.W Norton and co.

Cita Chicago (17th ed.)

KEETON, William T. Biological Science.-- Ed.3. New York: W.W Norton and co, 1980.

Cita MLA (9th ed.)

KEETON, William T. Biological Science.-- Ed.3. W.W Norton and co, 1980.