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
According to Roberts, tumors of the genital tract of the mare are a rare occurrence. Dimock and Edwards reported only six genital tumors in the examination of 2,000 mares. Of these tumors only three were found in the ovary, and none of these were teratomas.
"Equine Ovarian Teratoma: A Case Report,"
Iowa State University Veterinarian: Vol. 30
, Article 3.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol30/iss2/3