Pennak, R.W. 1953. Fresh-water Invertebrates of the United States. The Ronald Press Co., New York.

Smith, D.G. 2001. Pennak's Freshwater Invertebrates of the United States. 4th Ed. Porifera to Crustacea. John Wiley & Sons, Inc, New York.

Moser, W.E, F.R. Govedich, A. Oceguera-Figueroa, D.J. Richardson and A.J. Phillips. 2016. Subclass Hirudinida. In J.H. Thorp and D.C. Rogers (Eds.) Keys to Nearctic Fauna, Thorp and Covich's Freshwater Invertebrates - Volume II. Academic Press. Amsterdam

References
Water Worms (Oligochaeta) of Ohio