Viksnins, G. J. (1987). Economic systems in historical perspective. Kendal/Hunt Publishing Co.
Lua i Stíl Chicago (17ú heag.)Viksnins, George J. Economic Systems in Historical Perspective. Kendal/Hunt Publishing Co, 1987.
Lua MLA (8ú heag.)Viksnins, George J. Economic Systems in Historical Perspective. Kendal/Hunt Publishing Co, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.