Role of quality control circle in sustained improvement of hand hygiene compliance: an observational study in a stomatology hospital in Shandong, China - Peng Chen; Ting Yuan; Qinfeng Sun; Lili Jiang; Hongmin Jiang; Zhenkun Zhu; Zexin Tao; Haiyan Wang; Aiqiang Xu (Antimicrobial Resistance and Infection Control, 2016)