Michel Laurin (1991). «The osteology of a Lower Permian eosuchian from Texas and a review of diapsid phylogeny». Zoological Journal of the Linnean Society101 (1): 59-95. doi:10.1111/j.1096-3642.1991.tb00886.x.
Robert R. Reisz, Michel Laurin and David Marjanović (2010). «Apsisaurus witteri from the Lower Permian of Texas: yet another small varanopid synapsid, not a diapsid». Journal of Vertebrate Paleontology30 (5): 1628-1631. doi:10.1080/02724634.2010.501441.