APA Citation

 Buffett, W. (2007).  Warren Buffett speaks: Wit and wisdom from the world’s greatest investor.  John Wiley & Sons.

Chicago Style Citation

 Buffett, Warren.  Warren Buffett Speaks: Wit and Wisdom From the World’s Greatest Investor.  John Wiley & Sons, 2007.

MLA Citation

 Buffett, Warren.  Warren Buffett Speaks: Wit and Wisdom From the World’s Greatest Investor.  John Wiley & Sons, 2007.

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