APA (7th ed.) Citation

Allen. (2001). Getting things done: The art of stress-free productivity. Penguin Books.

Chicago Style (17th ed.) Citation

Allen. Getting Things Done: The Art of Stress-free Productivity. New York: Penguin Books, 2001.

MLA (8th ed.) Citation

Allen. Getting Things Done: The Art of Stress-free Productivity. Penguin Books, 2001.

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