http://en.wikipedia.org/wiki/2014_FI...F_Fourth_Round
The fourth round will see the three group winners and three runners-up from the third round compete in a double round robin, including a home and away match against the other five teams between 6 February and 15 October 2013. The round is informally referred to as the 'Hexagonal' or just 'The Hex'.[9]
The top three teams will qualify directly for the 2014 FIFA World Cup finals, while the fourth-placed team will play a home-away series against the winner of Oceania.