The papers I have found for today are all about that crazy frill of Styracosaurus, well, mostly about the frill. The first paper appeared in a 2007 JVP issue (be sure you read the republication warning on the front page and do things all legal-like) and examines the Styracosaurus genus almost three years before Paul's account placed Styracosaurus in the Centrosaur genus. This paper, however, retained the Styracosaur genus and even claimed that a second species, Styracosaurus ovatus, was a legitimate species separation from S. albertensis. The paper contains well detailed and labeled skull diagrams as well.
The second article and third article are by Peter Dodson and McDonald and Horner, respectively. Both papers discuss comparative craniology, anatomy of the skull, of Styracosaurus and other ceratopsian dinosaurs. McDonald and Horner are a bit more specific in discussing new material, as of 2010, attributed to S. ovatus. Their overall conclusion is fairly interesting and it's worth reading, but I'll leave it as a surprise for your reading pleasure. Dodson's 1993 paper on comparative anatomy of the skull discusses, or attempts to as it is a big family, the whole of ceratopsia but achieves a fair level of intimate detail on each species, Styracosaurus being one of those species. As a discussion on the cranial morphologies of these animals it is a very good paper to read and highly educational. If you are not into the bone structure of dinosaurs as much as I am, you may find it a little less interesting though.