Villegas, B. M., & Abola, V. A. (1982). Economics: An introduction. Sinag-Tala Pub.
Lua i Stíl Chicago (17ú heag.)Villegas, Bernardo M., agus Victor A. Abola. Economics: An Introduction. Manila: Sinag-Tala Pub, 1982.
Lua MLA (9ú heag.)Villegas, Bernardo M., agus Victor A. Abola. Economics: An Introduction. Sinag-Tala Pub, 1982.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.