Phylogeny of Arenig to Caradoc crinoids (Phylum Echinodermata) and suprageneric classification of the Crinoidea
Treatise Online no. 145: Part T, Revised, Chapter 6: Glossary of patterns, abbreviations, and symbols used to designate crinoid morphology
Treatise Online no. 150: Part T, Revised, Volume 1, Chapter 16: Feeding and arm postures in living and fossil crinoids