APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (8th ed.) Citation

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

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