APA (7th ed.) Citation

Heckman, J. (1998). Characterizing selection bias using experimental data. National Bureau of Economic Research.

Chicago Style (17th ed.) Citation

Heckman, James. Characterizing Selection Bias Using Experimental Data. Cambridge: National Bureau of Economic Research, 1998.

MLA (9th ed.) Citation

Heckman, James. Characterizing Selection Bias Using Experimental Data. National Bureau of Economic Research, 1998.