APA (7th ed.) Citation

DE BONO. (1990). The happiness purpose. Penguin Books.

Chicago Style (17th ed.) Citation

DE BONO. The Happiness Purpose. London: Penguin Books, 1990.

MLA (9th ed.) Citation

DE BONO. The Happiness Purpose. Penguin Books, 1990.

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