論文（英文）
Estimation of the average causal effect among subgroups defined by post-treatment variables.
Matsuyama Y and Morita S. Estimation of the average causal effect among subgroups defined by post-treatment variables. Clinical Trials 2006; 3: 1-9.
Matsuyama Y and Morita S. Estimation of the average causal effect among subgroups defined by post-treatment variables. Clinical Trials 2006; 3: 1-9.