APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

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

MLA (9e ed.) Bronvermelding

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

Let op: Deze citaties zijn niet altijd 100% accuraat.