Levine, P. B., & Staiger, D. (2001). Abortion as insurance. National Bureau of Economic Research.
Citazione stile Chigago Style (17a edizione)Levine, Phillip B., e Douglas Staiger. Abortion as Insurance. Cambridge: National Bureau of Economic Research, 2001.
Citatione MLA (9a ed.)Levine, Phillip B., e Douglas Staiger. Abortion as Insurance. National Bureau of Economic Research, 2001.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.