https://books.google.com.au/books?id=GqIctb8IqPoC
Pennak's Freshwater Invertebrates of the United States: Porifera to Crustacea - Douglas Grant Smith...
Need-to-know information on the classification and identificationof aquatic invertebrates This Fourth Edition of the standard reference used by generationsof...
https://species.wikimedia.org/wiki/Category:Robert_William_Pennak_taxa
Category:Robert William Pennak taxa - Wikispecies
categoryrobertwilliamtaxawikispecies