Jope, H. M., A. J. Rowell, Alwyn Williams, and M. J. S. Rudwick. 1965. “Part H, Brachiopoda, Vol. 1 & 2, Ch. 2, P. 157-256”. Treatise on Invertebrate Paleontology, January. https://doi.org/10.17161/dt.v0i0.5544.