APA (7th ed.) Citation

Sinek, S. (2009). Start with why: How great leaders inspire everyone to take action / Simon Sinek. Portfolio / Penguin.

Chicago Style (17th ed.) Citation

Sinek, Simon. Start with Why: How Great Leaders Inspire Everyone to Take Action / Simon Sinek. New York: Portfolio / Penguin, 2009.

MLA (9th ed.) Citation

Sinek, Simon. Start with Why: How Great Leaders Inspire Everyone to Take Action / Simon Sinek. Portfolio / Penguin, 2009.

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