James A. Campbell, Michael J. Ryan, Claudia J. Schröder-Adams, David C. Evans & Robert B. Holmes (2018). New insights into chasmosaurine (Dinosauria: Ceratopsidae) skulls from the Upper Cretaceous (Campanian) of Alberta, and an update on the distribution of accessory frill fenestrae in Chasmosaurinae. PeerJ6:e5194. doi: https://doi.org/10.7717/peerj.5194