1. Ducassi, E. R. and N. D. Smith: Colloid carcinoma in anal fistula: Report of two cases. Proc. Staff Meet., Mayo Clin.20: 57, 1945.
2. McAnally, A. K. and M. B. Dockerty: Carcinoma developing in chronic draining cutaneous sinuses and fistulas. Surg., Gynec. & Obst.88: 87, 1949.
3. Rosser, C.: The etiology of anal cancer. Am. J. Surg.11: 328, 1931.
4. Rosser, C.: The relation of fistula in ano to cancer of the anal canal. Tr. Am. Proct. Soc.35: 65, 1934.
5. Skir, I.: Mucinous carcinoma associated with listulas of long-standing. Am. J. Surg.75: 285, 1948.