Kohler, H. (1992). Economics. D.C. Heath and Company.
Lua i Stíl Chicago (17ú heag.)Kohler, Heinz. Economics. Lexington: D.C. Heath and Company, 1992.
Lua MLA (9ú heag.)Kohler, Heinz. Economics. D.C. Heath and Company, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.