Hillis, N. D. (1913). The quest of happiness: A study of victory over life's troubles. The Macmillan company; Macmillan & co., ltd..
Lua i Stíl Chicago (17ú heag.)Hillis, Newell Dwight. The Quest of Happiness: A Study of Victory over Life's Troubles. New York, London: The Macmillan company; Macmillan & co., ltd., 1913.
Lua MLA (8ú heag.)Hillis, Newell Dwight. The Quest of Happiness: A Study of Victory over Life's Troubles. The Macmillan company; Macmillan & co., ltd., 1913.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.