APA (7th ed.) Citation

Heckman, J. J., Lochner, L., & Todd, P. (2008). Earnings functions and rates of return. National Bureau of Economic Research.

Chicago Style (17th ed.) Citation

Heckman, James J., Lance Lochner, and Petra Todd. Earnings Functions and Rates of Return. Cambridge, Mass: National Bureau of Economic Research, 2008.

MLA (9th ed.) Citation

Heckman, James J., et al. Earnings Functions and Rates of Return. National Bureau of Economic Research, 2008.