- Pop 1975
- Was ist Hystricosoma chappuisi Michaelsen (Aeolosomatidae, Oligochaeta)? Mitteilungen aus den Zoologischen Staatsinstitut und Zoologischen Museum in Hamburg 72: 75-78.
- Holmquist 1983
- What is Tubifex tubifex (O.F. Müller) (Oligochaeta, Tubificidae)? Zoologica Scripta 12(3): 187-201.
- Coates 1995
- Widespread polyploid forms of Lumbricillus lineatus (Müller) (Enchytraeidae: Oligochaeta): comments on polyploidism in the enchytraeids. Canadian Journal of Zoology 73: 1727-1734.