1. Title:One-sided control charts for the mean of positively skewed distributions
Source:Total Quality Management & Business Excellence
       Volume 13, Issue 7, 2002, Pages 1021 - 1033
Authors: Yi Dou; Ping Sa
Link:http://www.informaworld.com/smpp ... ~content=a713600716

2. Title: X and R Control Charts for Skewed Populations
Source: Journal of Quality Technology, Vol. 27, No. 2, April 1995, pp. 120-131
Author: Bai, D.S.; Choi, I.S.
Link:http://asq.org/qic/display-item/?item=11404

谢谢！！！