Question: What FIFA World Cup did the referee of the 28 May 2011 football match at Wembley Stadium participate in? 
Sentence (from "2011 UEFA Champions League Final"): The 2011 UEFA Champions League Final was a football match played on 28 May 2011 at Wembley Stadium in London that decided the winner of the 2010–11 season of the UEFA Champions League.
Relevant evidence: Yes