1. Nothman BJ, Schuster MM. Internal anal sphincter derangement with anal fissures. Gastroenterology 1974;67:216–20.
2. Notaras MJ. Anal fissure and stenosis. Surg Clin North Am 1988;68:1427–41.
3. Goldberg SM, Gordon PH, Nivatvongs S. Essentials of anorectal surgery. Philadelphia: JB Lippincott, 1980.
4. Olsen J, Mortsen PE, Peterson K, Christiansen J. Anal sphincter function after treatment of fissure-in-ano by lateral subcutaneous sphincterotomy versus anal dilatation, a randomized study. Int J Colorectal Dis 1987;165:46–8.
5. Eisenhammer S. The surgical correction of chronic anal (sphincteric) contracture. S Afr Med J 1951;25:486–9.