A. C.  Stephen and Edmonds, S. J., The phyla Sipuncula and Echiura. London: Trustees British Mus. (Nat. Hist.), 1972, p. 528 pp.

M. E.  Rice and MacIntyre, I. G., ?A preliminary study of sipunculan burrows in rock thin sections?, Caribbean Journal of Science, vol. 12, pp. 41-44, 1972.