what are three examples of an oigopoly;

what are three examples of a monopolistic competition?

thank you!

http://www.investopedia.com/terms/o/oligopoly.asp#axzz2Lx7exjw6

http://www.investopedia.com/terms/m/monopolisticmarket.asp#axzz2Lx7exjw6

http://en.wikipedia.org/wiki/Monopolistic_competition