1. J. M. Adrain, 1997 .Proetid trilobites from the Silurian (Wenlock-Ludlow) of the Cape Phillips Formation, Canadian Arctic Archipelago., Palaeontographia Italica, 84 :21 –111 .
2. J. M. Adrain, and B. D E. Chatterton .1996 .The otarionine trilobiteCyphaspis,with new species from the Silurian of northwestern Canada., Journal of Paleontology, 70 :100 –110 .
3. J. M. Adrain, and R. A. Fortey .1997 .Ordovician trilobites from the Tourmakeady Limestone, western Ireland. Bulletin of the Natural History Museum, London., Geology Series, 53 :79 –115 .
4. W. D. Boyce, 1989 .Early Ordovician trilobite faunas of the Boat Harbour and Catoche Formations (St. George Group) in the Boat Harbour-Cape Norman area, Great Northern Peninsula, western Newfoundland. Newfoundland Department of Mines and Energy, Geological Survey Branch, Report, 89- 2 :1 –169 .
5. K. D. Brett, and S. R. Westrop .1996 .Trilobites of the Lower Ordovician (Ibexian) Fort Cassin Formation, Champlain Valley regions, New York State and Vermont., Journal of Paleontology, 70 :408 –427 .