McNulty, C.L. & Slaughter, B.H. (1972)
The Cretaceous Selachian Genus, Ptychotrygon JAEKEL 1894. Eclogae Geologicae Helvetiae, 65(3), 647–656

Welton, B.J. & Farish, R.F. (1993)
The collector's guide to fossil sharks and rays from the Cretaceous of Texas. Before Time, Lewisville, 1993

Ouroumova, O. & Shimada, K. & Kirkland, J.I. (2016)
Fossil Marine Vertebrates from the Blue Hill Shale Member (Middle Turonian) of the Upper Cretaceous Carlile Shale in Northeastern Nebraska. Transactions of the Kansas Academy of Science, 119(2), 211–221
DOI: 10.1660/062.119.0213