Alden, P. C. 1., Cassie, B. 1., Kahl, J. D. W., Oches, E. A., & Zirlin, H. (1999). National Audubon Society field guide to the Mid-Atlantic states (First edition.). New York: Alfred A. Knopf.

Alden, Peter C. 1944-, Brian 1953- Cassie, Jonathan D. W. Kahl, Eric A. Oches, and Harry Zirlin. National Audubon Society Field Guide to the Mid-Atlantic States. First edition. New York: Alfred A. Knopf, 1999.

Alden, Peter C. 1944-, et al. National Audubon Society Field Guide to the Mid-Atlantic States. First edition. New York: Alfred A. Knopf, 1999.