1. Counterfactuals.;Lewis,1973
2. Statistics and causal inference.;Holland;J Am Stat Assoc,1986
3. Comment on “Causal inference without counterfactuals.”;Robins;J Am Stat Assoc,2000
4. Summary Measures of Population Health.;Greenland,2002
5. Invited commentary: hypothetical interventions to define causal effects: afterthought or prerequisite?;Hernán;Am J Epidemiol,2005