Debono, E. (1977). The happiness purpose. Penguin.
Lua i Stíl Chicago (17ú heag.)Debono, Edward. The Happiness Purpose. England: Penguin, 1977.
Lua MLA (9ú heag.)Debono, Edward. The Happiness Purpose. Penguin, 1977.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.