Parkin, M. (1990). Economics. Addison-Wesley.
Lua i Stíl Chicago (17ú heag.)Parkin, Michael. Economics. Readings, Mass: Addison-Wesley, 1990.
Lua MLA (9ú heag.)Parkin, Michael. Economics. Addison-Wesley, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.