1. Perianal Crohn’s disease;Alexander-Williams;World J Surg,1980
2. Anorectal Crohn’s disease;McClans;Surg Clin North Am,2001
3. Carcinoma arising in anorectal fistulas of Crohn’s disease;Ky;Dis Colon Rectum,1998
4. Development of squamous cell carcinoma in chronic perineal sinus and wounds in Crohn’s disease;Buchman;Am J Gastroenterol,1991
5. Bailey & Love’s Short Practice of Surgery;Rains,1984