APA (7th ed.) Citation

Mulligan, C. B., & Sala i Martín, X. (1999). Social security in theory and practice. National Bureau of Economic Research.

Chicago Style (17th ed.) Citation

Mulligan, Casey B., and Xavier Sala i Martín. Social Security in Theory and Practice. Cambridge, MA: National Bureau of Economic Research, 1999.

MLA (9th ed.) Citation

Mulligan, Casey B., and Xavier Sala i Martín. Social Security in Theory and Practice. National Bureau of Economic Research, 1999.