Studies on non trilobite Arthropods of the Burgess shale (middle Cambrian). The genera Leanchoilia, Alalcomenaeus, Opabinia, Burgessia, Yohoia and Actaeus
A. Simonetta, Studies on non trilobite Arthropods of the Burgess shale (middle Cambrian). The genera Leanchoilia, Alalcomenaeus, Opabinia, Burgessia, Yohoia and Actaeus, Palaeontographia italica , 66, 1970, pp. 35-45