Applying Lean Six Sigma to Reduce the Incidence of Unplanned Surgery Cancellation at a Large Comprehensive Tertiary Hospital in China oleh Ling-Feng Zhu MB, Wei-Yang Qian MB, Gang Zhou MB, Min Yang MB, Jing-Jing Lin MB, Jing-Ling Jin BSc, Shu-Jing Dong MB, Lin-Hong Zhu MSc, Hai-Xiao Chen PhD