APA (7th ed.) Citation

Sinek. (2014). Leaders eat last: Why some teams pull together and others don't. Portfolio/?Penguin.

Chicago Style (17th ed.) Citation

Sinek. Leaders Eat Last: Why Some Teams Pull Together and Others Don't. New York: Portfolio/?Penguin, 2014.

MLA (8th ed.) Citation

Sinek. Leaders Eat Last: Why Some Teams Pull Together and Others Don't. Portfolio/?Penguin, 2014.

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