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 6-year-old grade Holstein dairy cow was referred to Stange Memorial Clinic because of dystocia. The cow was due to freshen and labor was noticed first some four hours before the patient was brought to the clinic. History revealed that for the past two months the cow's abdomen was becoming excessively large, but it was assumed by the owner that the cow was going to have twins.
Crawford, D. H.
"A Case of Dystocia Due to Hydrops Amnii Associated with a Fetal Monster.,"
Iowa State University Veterinarian: Vol. 12
, Article 10.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol12/iss1/10