Gardner, B. S. (1984). Economics: Study guide. Houghton Mifflin.
Lua i Stíl Chicago (17ú heag.)Gardner, Bronfenbrenner Sichel. Economics: Study Guide. Boston: Houghton Mifflin, 1984.
Lua MLA (9ú heag.)Gardner, Bronfenbrenner Sichel. Economics: Study Guide. Houghton Mifflin, 1984.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.