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
The prevalence of common intestinal parasites of dogs was determined and compared for the years 1965-68 and 1988 to determine what change, if any, has occurred in the prevalence of parasitisms over the past 20 years. Feces from dogs admitted to the Veterinary Teaching Hospital during these 2 periods were evaluated as part of the routine physical examination procedure. A sugar centrifugation method was used.
Greve, John H. and O'Brien, Susan E.
"Prevalence of Intestinal Parasites in Iowa Dogs A comparison between 1965-68 and 1988,"
Iowa State University Veterinarian: Vol. 51
, Article 7.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol51/iss1/7