Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
A one year-old Collie was submitted to Stange Memorial Clinic on Feb. 7, 1952. for treatment of a head injury. The owner stated that the dog had been kicked in the head by a horse two months previously. The patient had a fistulous opening at the prominence of the right frontal bone which was discharging a thick, greenish-yellow purulent exudate. The diagnosis was impression fracture of the frontal bone with secondary frontal sinusitis.
"Frontal Sinusitis in a Dog,"
Iowa State University Veterinarian: Vol. 14
, Article 13.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol14/iss3/13