Literature
- Muus, B.J. 1959. Skallus Søtaender Blaeksprutter. Danmarks Fauna, 65. Dansk Naturhistorisk Forening.
- Nesis, K.N. 1987. Cephalopods of the world. T.F.H. Publications, Inc., Ltd.
- Seaward, D.R. 1990. Distribution of the marine molluscs of north west Europe. Nature Conservancy Council.