Synapsid Classification and Autapomorphies
- A cladistic description with annotated diagrams.
- http://tolweb.org/tree/eukaryotes/animals/chordata/synapsid_lichen/synapsida_synapomorphies.html

Permian Geography
- Description and maps of the continents as they existed at the time.
- http://vishnu.glg.nau.edu/rcb/Permian.html

First Complete Gorgonopsid Skeleton Found
- An article describing the discovery of this late Permian predator.
- http://www.washington.edu/newsroom/news/1998archive/12-98archive/k120898.html

The Permian
- An overview of the period from the UC Berkeley Museum of Paleontology.
- http://www.ucmp.berkeley.edu/permian/permian.html

Systematics of the Synapsida
- Cladogram with links to pages on the Dinocephalids, Pelycosaurs, Dicynodonts, Cynodonts, Mammals and Gorgonopsids.
- http://www.ucmp.berkeley.edu/synapsids/synapsidasy.html