Spindler, F. (2019). "The skull of Tetraceratops insignis (Synapsida, Sphenacodontia)". Palaeovertebrata. 43 (1): e1. doi:10.18563/pv.43.1.e1. S2CID214247325.
Mazierski, D.M.; Reisz, R.R. (2010). "Description of a new specimen of Ianthasaurus hardestiorum (Eupelycosauria: Edaphosauridae) and a re-evaluation of edaphosaurid phylogeny". Canadian Journal of Earth Sciences. 47 (6): 901–912. Bibcode:2010CaJES..47..901M. doi:10.1139/E10-017.
Winston, R.B. (1983). "A late Pennsylvanian upland flora in Kansas: Systematics and environmental implications". Review of Palaeobotany and Palynology. 40 (1–2): 5–31. Bibcode:1983RPaPa..40....5W. doi:10.1016/0034-6667(83)90003-9.
Kerp, J.H.F.; Haubold, H. (1988). "Aspects of Permian palaeobotany and palynology. VIII. On the reclassification of the West-and Central European species of the form-genus Callipteris Brongniart 1849". Review of Palaeobotany and Palynology. 54 (1–2): 135–150. Bibcode:1988RPaPa..54..135K. doi:10.1016/0034-6667(88)90009-7.
Mazierski, D.M.; Reisz, R.R. (2010). "Description of a new specimen of Ianthasaurus hardestiorum (Eupelycosauria: Edaphosauridae) and a re-evaluation of edaphosaurid phylogeny". Canadian Journal of Earth Sciences. 47 (6): 901–912. Bibcode:2010CaJES..47..901M. doi:10.1139/E10-017.
Winston, R.B. (1983). "A late Pennsylvanian upland flora in Kansas: Systematics and environmental implications". Review of Palaeobotany and Palynology. 40 (1–2): 5–31. Bibcode:1983RPaPa..40....5W. doi:10.1016/0034-6667(83)90003-9.
Kerp, J.H.F.; Haubold, H. (1988). "Aspects of Permian palaeobotany and palynology. VIII. On the reclassification of the West-and Central European species of the form-genus Callipteris Brongniart 1849". Review of Palaeobotany and Palynology. 54 (1–2): 135–150. Bibcode:1988RPaPa..54..135K. doi:10.1016/0034-6667(88)90009-7.
Reisz, R.R.; Heaton, M.J.; Pynn, B.R. (1982). "Vertebrate fauna of late Pennsylvanian rock lake shale near Garnett, Kansas: Pelycosauria". Journal of Paleontology. 56 (3): 741–750. JSTOR1304403.
Currie, P.J. (1977). "A new haptodontine sphenacodont (Reptilia: Pelycosauria) from the Upper Pennsylvanian of North America". Journal of Paleontology. 51 (5): 927–942. JSTOR1303764.