Παραπομπή APA

Lettau, M. 1., Ludvigson, S. C. 1., & National Bureau of Economic Research. (2003). is the social security trust fund worth anything. Cambridge: National Bureau of Economic Research.

Παραπομπή Chicago Style

Lettau, Martin 1966-, Sydney C. 1964- Ludvigson, and National Bureau of Economic Research. Is the Social Security Trust Fund Worth Anything. Cambridge: National Bureau of Economic Research, 2003.

Παραπομπή MLA

Lettau, Martin 1966-, Sydney C. 1964- Ludvigson, and National Bureau of Economic Research. Is the Social Security Trust Fund Worth Anything. Cambridge: National Bureau of Economic Research, 2003.

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