1. and further reading DIERAUF, L. A. (Ed) (1990) CRC
2. Guide to the Identification of Whales, Dolphins and Porpoises in European Seas;EVANS, P.G.H.,1995
3. Zoo and wild animal medicine: current therapy 3. In Marine Mammals;FOWLER, M.E.,1993
4. Philadelphia, W. B. Saunders. pp 412-427 GERACI, J. R. & LOUNSBURY, V. J. (1993) Marine Mammals
5. Diseases of Marine Animals, Volume IV. Part 2;KINNE, 0,1985