Pennak, R. W. (1989). Fresh-water invertebrates of the United States: Protozoa to mollusca (3rd ed.). New York: Wiley.
Chicago Style CitationPennak, Robert W. Fresh-water Invertebrates of the United States: Protozoa to Mollusca. 3rd ed. New York: Wiley, 1989.
MLA CitationPennak, Robert W. Fresh-water Invertebrates of the United States: Protozoa to Mollusca. 3rd ed. New York: Wiley, 1989.
Warning: These citations may not always be 100% accurate.