R. P. · Robert P. · Robert W. · W.P.
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Fresh-water invertebrates of the United States | 978-0-471-04249-5 (0-471-04249-8) | 1978 |
| Pennak's Freshwater Invertebrates of the United States: Porifera to Crustacea | 978-0-471-35837-4 (0-471-35837-1) | 2001 |