Rigby, J. K.; Collins, D. (2004). "Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia". ROM contributions in science. 1. ISBN 0-88854-443-X. ISSN 1710-7768.
Rigby, J. K.; Collins, D. (2004). "Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia". ROM contributions in science. 1. ISBN 0-88854-443-X. ISSN 1710-7768.