Levitt, S. D. (2009). Freakonomics. Harper Collins.
Lua i Stíl Chicago (17ú heag.)Levitt, Steven D. Freakonomics. Harper Collins, 2009.
Lua MLA (9ú heag.)Levitt, Steven D. Freakonomics. Harper Collins, 2009.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.