APA (7th ed.) Citation

(1955). Keys to happiness: A Reader's Digest guide to successful living. The Reader's Digest Association.

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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

Warning: These citations may not always be 100% accurate.