1. Dietz, T. H. and Alvaredo, R. H., 1970. Osmotic and ionic regulation in Lumbricus terrestris L. Biol. Bull. 138: 247–261.
2. Ditlevsen, A., 1904. Studien an Oligochäten. Z. Wiss. Zool. 77: 389–480.
3. Elrick, D. L., 1976. The morphology, reproduction, and ecology of Colorado species of Chaetogaster (Oligochaeta, Annelida). Ph.D. Thesis. Univ. Colorado, Boulder. 311 pp.
4. Falls, E. Q., 1975. A taxonomic survey of freshwater oligochaetes of the Richmond, Virginia area with special reference to commensal ciliates. Virginia J. Sci. 26: 26–29.
5. Harman, W. J. & Platt, J. H., 1961. Notes on some aquatic oligochaetes from Louisiana. Proc. Louisiana Acad. Sci. 20: 90–95.