Fish, J.D.; Fish, S. (2011). Hemichordata, in: Fish, J.D. et al.A student's guide to the seashore. pp. 427-428
In: Fish, J.D.; Fish, S. (2011). A student's guide to the seashore. Third edition. Cambridge University Press: Cambridge. ISBN 978-0-521-72059-5. 527 pp. https://dx.doi.org/10.1017/CBO9781139035125, more
