Hamm, S. (2009). Online interest in UFC skyrockets while Nascar, NF land NHL fall. Newswire. Disponível em: <http://www.nielsen.com/us/en/newswire/2009/online-interest-in-ufc-skyrockets-while-nascar-nfl-and-nhl-fall-2.html>. Acesso em: 02 de agosto de 2013.