Pennak, R. . W. (1953). Fresh-water invertebrates of the United States. Wiley.
Dyfyniad Arddull ChicagoPennak, Robert W. Fresh-water Invertebrates of the United States. New York: Wiley, 1953.
Dyfyniad MLAPennak, Robert W. Fresh-water Invertebrates of the United States. Wiley, 1953.
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