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
That there are potential dangers associated with ionizing radiation has been recognized almost from the time of discovery of x-rays by Wilhelm Roentgen in 1895. During the past 50 years there have appeared numerous accounts and warnings of these dangers in the medical literature. In more recent years there have been several authoritative articles in veterinary literature describing x-ray hazards and protection recommendations.
Wolff, A. H.
"Veterinary X-Ray Protection,"
Iowa State University Veterinarian: Vol. 17
, Article 2.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol17/iss1/2