1. Silverberg E, Lubera J. Cancer Statistics 1987 CA 1987;37:2–19.
2. Cattell RB, Williams AC. Epidermoid cancer of the anus and rectum. Arch Surg 1943;46:336–49
3. Morson BC. The pathology and results of treatment of cancer of the alal region. Proc R Soc Med 1959;52:S117–8.
4. Richards JC, Beahrs OH, Woolner LB. Squamous cell carcinoma of the anus, anal canal and rectum in 109 patients. Surg Gynecol Obstet 1962;114:474–82.
5. Sweet RH. Results of treatment of epidermoid carcinoma of the anus and rectum. Surg Gynecol Obstet 1947;84:967–72.