論文（英文）
Hagiwara Y, Fukuda M, Matsuyama Y. The Number of Events per Confounder for Valid Estimation of Risk Difference Using Modified Least-Squares Regression. Am J Epidemiol. Accepted.
Hagiwara Y, Fukuda M, Matsuyama Y. The number of events per confounder for valid estimation of risk difference using modified least-squares regression. Am J Epidemiol. 2018;187:2481-2490.