Cita APA (7th ed.)

Mulligan, C. B., & Sala-i-Martin, X. (1999). Gerontocracy, retirement, and social security. National Bureau of Economic Research.

Cita Chicago (17th ed.)

Mulligan, Casey B., i Xavier Sala-i-Martin. Gerontocracy, Retirement, and Social Security. Cambridge: National Bureau of Economic Research, 1999.

Cita MLA (9th ed.)

Mulligan, Casey B., i Xavier Sala-i-Martin. Gerontocracy, Retirement, and Social Security. National Bureau of Economic Research, 1999.