5Boonjunwetwat D, Sungtong P, Rojanasakul A. Defecography in patients with anorectal disorders: a study in 27 cases. J Med Assoc Thai,2001,84:1097.
6Choi JS,Wexner SD, Nam YS, et al. Intraobserver and interobserver measurements of the anorectal angle and perineal descent in defecography. Dis Colon Rectum, 2000,43: 1121.