Mcadams, N. E.; Adrain, J. M.; Karim, T. S. (2018). The pliomerid trilobite Ibexaspis and related new genera, with species from the Early Ordovician (Floian; Tulean, Blackhillsian) of the Great Basin, western USA. Zootaxa. 4525(1): 1-152.
The pliomerid trilobite Ibexaspis and related new genera, with species from the Early Ordovician (Floian; Tulean, Blackhillsian) of the Great Basin, western USA