PENNAK, Robert W. Fresh-Water invertebrates of the United stated /by Robert W.Pennak - 2nd ed. - New York A Wiley-Interscience pub. 1978 - xv, 803 p. Includes appendix, references and index. ISBN: 471042498 Subjects--Topical Terms: Invertebrates Dewey Class. No.: 592 / PEN