Raven, P. H., Berg, L. R., & Johnson, G. B. (1993). Environment. Saunders College Pub.
Cita Chicago (17th ed.)Raven, Peter H., Linda R. Berg, i George Brooks Johnson. Environment. Fort Worth, TX: Saunders College Pub, 1993.
Cita MLA (9th ed.)Raven, Peter H., et al. Environment. Saunders College Pub, 1993.
Atenció: Aquestes cites poden no estar 100% correctes.