1. Abcarian H. Perianal Crohn's disease. Semin Colon Rectal Surg 1994;5:210–5.
2. Bartram CI, Burnett SJ. Atlas of anal endosonography. Oxford: Butterworth-Heinemann Ltd., 1991.
3. Bayer I, Gordon PH. Selected operative management of fistula-in-ano in Crohn's disease. Dis Colon Rectum 1994;37:760–5.
4. Beck DE, Wexner SD. Fundamentals of anorectal surgery. New York: McGraw-Hill, 1992:140–3.
5. Belliveau P. Anal fistula. In: Fazio VW, ed. Current therapy in colon and rectal surgery. Toronto: BC Decker, 1990:22–7.