APA (7th ed.) Citation

PURVES, W. K., & ORIANS, G. H. (1987). Life: The science of biology.-- ed.2. Sinauer Associates inc.

Chicago Style (17th ed.) Citation

PURVES, William K., and Gordon H. ORIANS. Life: The Science of Biology.-- Ed.2. Sunderland: Sinauer Associates inc, 1987.

MLA (9th ed.) Citation

PURVES, William K., and Gordon H. ORIANS. Life: The Science of Biology.-- Ed.2. Sinauer Associates inc, 1987.