Heckman, J. L. (1999). Causal parameters and policy analysis in economics: A twentieth century retrospective. National Bureau of Economic Research.
芝加哥风格引文Heckman, James L. Causal Parameters and Policy Analysis in Economics: A Twentieth Century Retrospective. Cambridge: National Bureau of Economic Research, 1999.
MLA引文Heckman, James L. Causal Parameters and Policy Analysis in Economics: A Twentieth Century Retrospective. National Bureau of Economic Research, 1999.
警告：这些引文格式不一定是100％准确.