Giersch, S. & Frey, E. & Ifrim, C. & Stinnesbeck, W. & Gonzales Gonzales, A.H. (2010)
Ptychodontid sharks from the Upper Cretaceous locality Vallecillo (North-eastern Mexico) [Abstract].
In Fifth international meeting on Mesozoic fishes – Universidad Autonoma de Estado de Hidalgo: 43
Stinnesbeck, W. & López-Oliva, J.G. & Frey, E. & Ifrim, C. & Giersch, S. (2008)
Comments on "The oldest stratigraphic record of the Late Cretaceous shark Ptychodus mortoni Agassiz, from Vallecillo, Nuevo León, northeastern Mexico'' by Blanco-Piñón et al., Rev. Mex. Cienc. Geol. (2007), 24, 25-30
Revista Mexicana de Ciencias Geológicas, 25(2), 365–366