Distributions of Cranial Pathologies Provide Evidence for Head-Butting in Dome-Headed Dinosaurs (Pachycephalosauridae) Peterson, Joseph E. ; Dischler, Collin ; Longrich, Nicholas R. Abstract Publication: PLoS ONE Pub Date: July 2013 DOI: 10.1371/journal.pone.0068620 Bibcode: 2013PLoSO...868620P