Priapulids, sipunculans, echiurans and entoprocts (Phyla Priapulida, Sipuncula, Echiura and Entoprocta)
Knight-Jones, E.W.; Ryland, J.S. (1996). Priapulids, sipunculans, echiurans and entoprocts (Phyla Priapulida, Sipuncula, Echiura and Entoprocta), in: Hayward, P.J. et al. (1995). Handbook of the marine fauna of North-West Europe. pp. 278-288
In: Hayward, P.J.; Ryland, J.S. (Ed.) (1995). Handbook of the marine fauna of North-West Europe. First edition. Oxford University Press: Oxford. ISBN 0-19-854054-X. XI, 800 pp., meer
