Leftwich, R. H. (1982). Economics of social issues (5ª ed.). Business.
Lua i Stíl Chicago (17ú heag.)Leftwich, Richard H. Economics of Social Issues. 5ª ed. Business, 1982.
Lua MLA (9ú heag.)Leftwich, Richard H. Economics of Social Issues. 5ª ed. Business, 1982.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.