This document references four sources about crustaceans and freshwater isopods in North America: Hickman et al.'s 2012 animal diversity textbook discusses isopods on pages 245-265; Richardson's 1905 monograph describes North American isopods from pages 409-433; Williams' 1970 paper revises epigean species of the genus Asellus based on specimens from the Smithsonian Institution; Williams' 1972 EPA work provides a guide to freshwater isopods of North America.