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
Ear trimming, more correctly termed partial conchal amputation, is not an operation condoned by the veterinarian. However, since the dictates of custom and fancy have made it vogue in certain breeds, it has become necessary for the small animal practitioner to become familiar with this operation. The following discussion is written with the Boxer in mind, but the same basic procedure may be applied to ear trimming in other breeds.
Covault, C. H.
"Boxer Ear Trim,"
Iowa State University Veterinarian: Vol. 15
, Article 3.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol15/iss3/3