HUBBARD, R. G. (2017). Economics. Pearson Education.
Lua i Stíl Chicago (17ú heag.)HUBBARD, R. Glenn. Economics. Pearson Education, 2017.
Lua MLA (9ú heag.)HUBBARD, R. Glenn. Economics. Pearson Education, 2017.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.