MaCleod, N. (1982)
The first North American occurrence of the Late Cretaceous elasmobranch Ptychodus rugosus Dixon with comments of the functional morphology of the dentition and dermal denticles. Journal of Paleontology, 56(2), 403–409
MaCleod, N. & Slaughter, B.H. (1980)
A new ptychodontid shark from the Upper Cretaceous of Northeast Texas. Texas Journal of Science, 32(4), 333–335