Literature
  • Picton, Morrow 1994
  • A field guide to the Nudibranches of the British Isles. Immel Publishing Limited.
  • Picton 1993
  • A field guide to the shallow-water Echinoderms of the British Isles. Immel Publishing Limited.
  • Newton 1931
  • A handbook of the British seaweeds. British Museum (Natural History), London.
  • Knight-Jones, Ryland 1995
  • Acorn-worms and Sea squirts (Phyla Hemichordata and Urochordata). In: Handbook of the Marine Fauna of North-West Europe. (ed. P.J. Hayward & J.S. Ryland). Oxford University Press, Oxford.