1. P. Legendre and L. Legendre "Numerical ecology." (1998)
2. "NatureServe Explorer." (2023)
3. "Global Biodiversity Information Facility." (2023)
4. J. B. Burch, "North American Freshwater Snails." (1989)
5. J. B. Burch and Y. Jung "Walkerana." 6, "Freshwater snails of the University of Michigan Biological Station area." 1 (1992)