Increased quality of bowel preparation via smartphone WeChat application: a multicenter randomized controlled trial - Jing Wen; Jia Feng; Cuihua Liu; Dianhui Yang; Yangyang Zhang; Nali Lu; Jianmei Yu; Yanxin Gao; Ruli Sheng; Jianhua Wang; Jin Huang (Videosurgery and Other Miniinvasive Techniques)