D. Maddox and W. P. Wall. 1998. A systematic review of the fossil lizards and snakes (Squamata) from the White River Group of Badlands National Park. In V. L. Santucci and L. McClelland (eds.), National Park Service Paleontological Research Vol. 3 Technical Report NPS/NRGRD/GRDTR-98/1 4-7 [J. Alroy/J. Alroy]