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 2-year-old, grade, Brown Swiss cow was referred to Stange Memorial Clinic Dec. 6, 1950. This animal had a history of respiratory distress which had seemingly failed to respond to all treatment.
Mattison, James R.
"Idiopathic Pulmonary Emphysema in a Cow,"
Iowa State University Veterinarian: Vol. 13
, Article 18.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol13/iss2/18