1. Abushik, A.F., R.B. Blodgett, and V.V. Baranov. 2016. The first early Lochkovian ostracods in redbeds of the Karheen Formation of Prince of Wales Island (Southeast Alaska). New Mexico Museum of Natural History and Science Bulletin 74: 1–4.
2. Anderson, L.I., M. Poschmann, and C. Brauckmann. 1998. On the Emsian (Lower Devonian) arthropods of the Rhenish Slate Mountains: 2. The synziphosurine Willwerathia. Paläontologische Zeitschrift 72: 325–336.
3. Babcock, L.E., D.F. Merriam, and R.R. West. 2000. Paleolimulus, an early limuline (Xiphosurida), from Pennsylvanian-Permian Lagerstätten of Kansas and taphonomic comparison with modern Limulus. Lethaia 33: 129–141.
4. Botting, J.P. 2007. Algae, receptaculitids and sponges. In Silurian fossils of the Pentland Hills, Scotland, eds. E.N.K. Clarkson, D.A.T. Harper, C.M. Taylor, and L.I. Anderson, 36–49. London: The Palaeontological Association.
5. Burmeister, H. 1843. Die Organisation der Trilobiten, aus ihren lebenden Verwandten entwickelt; nebst einer systematische Uebersicht aller zeither beschriebenen Arten, 1–148. Berlin: G. Reimer.