Question: What FIFA World Cup did the referee of the 28 May 2011 football match at Wembley Stadium participate in? 

full_context: Document 1: 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. The winners received the European Champion Clubs' Cup (the European Cup). The 2011 final was the culmination of the 56th season of the tournament, and the 19th in the Champions League era.
Document 2: 2010 FIFA World Cup Final: The 2010 FIFA World Cup Final (also known as the Battle of Johannesburg) was a football match that took place on 11 July 2010 at Soccer City in Johannesburg, South Africa, to determine the winner of the 2010 FIFA World Cup. Spain defeated the Netherlands 1–0 with a goal from Andrés Iniesta four minutes from the end of extra time. English referee Howard Webb was selected to officiate the match, which was marked by an unusually high number of yellow cards.
Document 3: 2011 FA Cup Final: The 2011 FA Cup Final was the 130th final of the FA Cup, the world's oldest domestic football cup competition. The final took place on 14 May 2011 at Wembley Stadium in London in front of 88,643 spectators and a British television audience of more than eight million. The clubs contesting the final were Premier League clubs Manchester City and Stoke City. The match was Stoke City's first FA Cup final, and Manchester City's ninth.
Document 4: 2010 UEFA Champions League Final: The 2010 UEFA Champions League Final was a football match played at the Santiago Bernabéu Stadium, home of Real Madrid, on Saturday, 22 May 2010, to determine the winners of the 2009–10 UEFA Champions League. It was the first Champions League final to be played on a Saturday, rather than the traditional Wednesday. The match was won by Internazionale, who beat Bayern Munich 2–0 to complete the Treble, a feat never before achieved by any team from either Italy or Germany. The refereeing team came from England and was led by Howard Webb.
Document 5: Carlos Vera: Carlos Alfredo Vera Rodríguez (born June 25, 1976) is an Ecuadorian football referee. He has been an international referee since 2006. He has officiated matches in FIFA World Cup qualifiers, the Copa Libertadores, the Copa Sudamericana and the South American Youth Football Championship. He was selected as a referee for the 2011 Copa América in Argentina and the 2015 Copa America in Chile. In addition, he was appointed by FIFA to take charge of matches at the 2012 FIFA Club World Cup and the 2014 FIFA World Cup. He was selected as the fourth official for the 2014 FIFA World Cup Final.
Document 6: 2011 Football League Cup Final: The 2011 Football League Cup Final was the final match of the 2010–11 Football League Cup, the 51st season of the Football League Cup, a football competition for the 92 teams in the Premier League and the Football League. The match was contested by Arsenal and Birmingham City, at Wembley Stadium in London, on 27 February 2011. It was broadcast live on the BBC and Sky Sports. Birmingham City won the game 2–1 and were guaranteed a spot in the third qualifying round of the 2011–12 UEFA Europa League. Mike Dean was the referee.
Document 7: 2015 UEFA Champions League Final: The 2015 UEFA Champions League Final was the final match of the 2014–15 UEFA Champions League, the 60th season of Europe's premier club football tournament organised by UEFA, and the 23rd season since it was renamed from the European Champion Clubs' Cup to the UEFA Champions League. It was played at the Olympiastadion in Berlin, Germany, on 6 June 2015, between Italian side Juventus and Spanish side Barcelona.
Document 8: 2016 UEFA Champions League Final: The 2016 UEFA Champions League Final was the final match of the 2015–16 UEFA Champions League, the 61st season of Europe's premier club football tournament organised by UEFA, and the 24th season since it was renamed from the European Champion Clubs' Cup to the UEFA Champions League. It was played at the San Siro stadium in Milan, Italy, on 28 May 2016, between Spanish teams Real Madrid and Atlético Madrid, in a repeat of the 2014 final. It was the second time in the tournament's history that both finalists were from the same city. Real Madrid won 5–3 on a penalty shoot-out after a 1–1 draw at the end of extra time, securing a record-extending 11th title in the competition.
Document 9: 2010 Leinster Senior Football Championship: The 2010 Leinster Senior Football Championship was that year's installment of the annual Leinster Senior Football Championship held under the auspices of the Leinster GAA. It was won by Meath who defeated Louth in an eventful final on 11 July. A contentious goal was given. Irate Louth fans pursued the referee around the pitch at the final whistle, bottles were hurled from the stand and the mayhem was compared to soccer player Thierry Henry's handball that cheated the Irish soccer team of their place at the 2010 FIFA World Cup the previous November. Coincidentally, 11 July was also the date of the 2010 FIFA World Cup Final, which was played in South Africa later in the evening.
Document 10: 2011 UEFA Europa League Final: The 2011 UEFA Europa League Final was the final match of the 2010–11 UEFA Europa League, the 40th season of Europe's secondary club football tournament organised by UEFA, and the second season since it was renamed from UEFA Cup to UEFA Europa League. The match was played at the Aviva Stadium in Dublin, Republic of Ireland, on 18 May 2011, between two Portuguese teams – Porto and Braga – for the first time in UEFA competition finals.
Document 11: 2017 UEFA Champions League Final: The 2017 UEFA Champions League Final was the final match of the 2016–17 UEFA Champions League, the 62nd season of Europe's premier club football tournament organised by UEFA, and the 25th season since it was renamed from the European Champion Clubs' Cup to the UEFA Champions League. It was played at the Millennium Stadium in Cardiff, Wales on 3 June 2017, between Italian side Juventus and Spanish side and title holders Real Madrid, in a repeat of the 1998 final. Real Madrid won the match 4–1 to secure their 12th title in this competition. With this victory, as the defending champions, Real Madrid became the first ever team to successfully defend their title in the Champions League era, and the first to do so since Milan in 1990. On the other hand, Juventus lost a fifth final in a row and a seventh in nine finals reached.
Document 12: Viktor Kassai: Viktor Kassai ("Kassai Viktor", : ; born 10 September 1975) is a Hungarian football referee. He participated in the 2010 FIFA World Cup and refereed the 2011 UEFA Champions League Final. He has been a full international referee for FIFA since 2003.
Document 13: 2009–10 UEFA Champions League: The 2009–10 UEFA Champions League was the 55th season of Europe's premier club football tournament organised by UEFA, and the 18th under the current UEFA Champions League format. The final was played on 22 May 2010, at the Santiago Bernabéu Stadium, home ground of Real Madrid, in Madrid, Spain. The final was won by Italian club Internazionale, who beat German side Bayern Munich 2–0. Internazionale went on to represent Europe in the 2010 FIFA Club World Cup, beating Congolese side TP Mazembe 3–0 in the final, and played in the 2010 UEFA Super Cup against Europa League winners Atlético Madrid, losing 2–0.
Document 14: Sándor Puhl: Sándor Puhl (born 14 July 1955) is a retired Hungarian football referee. He is mostly known for supervising four matches in the 1994 FIFA World Cup in the United States, including the final between Brazil and Italy. He also refereed UEFA Champions League matches, including the 1997 UEFA Champions League Final between Borussia Dortmund and Juventus. Dortmund ended up being 3-1 winners.
Document 15: Michel Kitabdjian: Michel Kitabdjian (born 7 May 1930 in Nice) is a French former referee. He officiated at the 1975 European Cup Final between Leeds United and Bayern Munich, disallowing a goal by Leeds United's Peter Lorimer for offside and denying Leeds two penalty appeals as Franz Beckenbauer first handled the ball in the box and then brought down Allan Clarke in a tackle. Leeds fans became angry at the referee, and one fan managed to access the playing field after the final whistle. After gendarmes removed him, other Leeds fans began rioting in the stands.
ground_truth: 2010 FIFA World Cup