1. Die pelagischen nemertinen;Brinkmann;Bergens Mus. Skrifter,1917
2. tlber der pharynx der heteropoden;Buchmann;Zeitsch. Anat. und Entwicklungsgeschichte,1924
3. The pelagic nemerteans;Coe;Mem. Mus. Compar. Zool. Harvard,1926
4. Day, J. H. 1967. A monograph on the polychaeta of Southern Africa. Pt. 1 (Errantia). British Museum of Natural History, Publ.No.656,458 pp, 17 figs. Fretter, V. and A. Graham. 1962. British prosobranch molluscs. Ray Society, London, No. 144,7 55 pp., 317 figs. Holiday, F. W. 1968. The great orm of Loch Ness, 223 pp.,15 figs.
5. Faber and Faber, London.