Cita APA (7a ed.)

(1955). Keys to happiness: : a reader ́s digest guide to successful living. The reader ́s Digest Association.

Cita Chicago Style (17a ed.)

Keys to Happiness: : A Reader ́s Digest Guide to Successful Living. Pleasantville (N.Y.): The reader ́s Digest Association, 1955.

Cita MLA (9a ed.)

Keys to Happiness: : A Reader ́s Digest Guide to Successful Living. The reader ́s Digest Association, 1955.