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 most common locations of urinary calculi in the dog are the renal pelvis, the urinary bladder and the male urethra. Most of these calculi are formed in the bladder. The chemical composition of cystic calculi is predominantly triple phosphates. Alterations in the pH together with the presence of bacteria, casts, epithelial cells and foreign material acting as a nucleus, predispose to calculus formation.
Lucas, James F.
"Urinary Calculi in a Boston Terrier,"
Iowa State University Veterinarian: Vol. 24
, Article 9.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol24/iss2/9