1. Doershuk CF, Boat TF. In: Behrman RE, Vaughan VC, eds. Nelson's textbook of pediatrics. 12th ed. Philadelphia: WB Saunders, 1983:1097.
2. Santulli TV. In: Rudolph AM, Hoffman JI, eds. Pediatrics. 17th ed. Norwalk: Appleton-Century-Crofts, 1983:990–1.
3. Goligher JC. Surgery of the anus, rectum and colon. 4th ed. London: Balliere Tindall, 1980:227–8.
4. Goldberg SM, Gordon PH, Nivatvongs S. Essentials of anorectal surgery. Philadelphia: JB Lippincott, 1980:266.
5. Gabriel WB. The principles and practice of rectal surgery. 5th ed. London: HK Lewis, 1963:173–5.