1. Art. IV. Illustrations in British zoology;Johnston;Mag Nat Hist Lond,1835
2. Zur Systematik der monogenetischen Trematoden;Taschenberg;Z Gesamte Naturwiss,1879
3. Udonella caligorum Johnston, 1835, a representative of a new class of flatworms;Ivanov;Zool Zhurnal,1952
4. Morphology of Udonella caligorum Johnston, 1835, and the position of Udonellidae in the systematics of platyhelminths;Ivanov;Parazitol Sb,1952