SAMPSON, R. J. (1983). The American Economy Analysis Issues Principles Roy J. Sampson And Ira Marienhoff. Houghton Mifflin Company.
Lua i Stíl Chicago (17ú heag.)SAMPSON, Roy J. The American Economy Analysis Issues Principles Roy J. Sampson And Ira Marienhoff. Houghton Mifflin Company, 1983.
Lua MLA (8ú heag.)SAMPSON, Roy J. The American Economy Analysis Issues Principles Roy J. Sampson And Ira Marienhoff. Houghton Mifflin Company, 1983.
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