Mulligan, C. B., & Sala-i-Martin, X. (1999). Social security in theory and practice (II): Facts and political theories. National Bureau of Economic Research.
Citação do estilo Chicago (17ª ed.)Mulligan, Casey B., e Xavier Sala-i-Martin. Social Security in Theory and Practice (II): Facts and Political Theories. Cambridge: National Bureau of Economic Research, 1999.
Citação MLA (9ª ed.)Mulligan, Casey B., e Xavier Sala-i-Martin. Social Security in Theory and Practice (II): Facts and Political Theories. National Bureau of Economic Research, 1999.
Nota: a formatação da citação pode não corresponder 100% ao definido pela respectiva norma.