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Ansolabehere, Stephen; John de Figueiredo; James M. Snyder, Jr. (2003). «Why Is There So Little Money in U.S. politics?». Journal of Economic Perspectives. 17: 105–30. CiteSeerX10.1.1.455.6486. doi:10.1257/089533003321164976
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Gill, David; Lipsmeyer, Christine (2005). Soft Money and Hard Choices: Why Political Parties Might Legislate Against Soft Money Donations. [S.l.]: Public Choice. SSRN1422616