[1]
Ubaghs, G. et al. 1968. Part S, Echinodermata 1, vol. 1 & 2 ,Ch. 5, p. 565 - 637.
Treatise on Invertebrate Paleontology
. (Jan. 1968). DOI:
https://doi.org/10.17161/dt.v0i0.5638
.