Legendary Teams: Manchester United's 1999 treble sparks the best stretch in the club's modern history - International Champions Cup

Manchester United, Sir Alex Ferguson and the 1999 Treble: That night in Barcelona - Eurosport

Legendary Teams: Manchester United's 1999 treble sparks the best stretch in the club's modern history - International Champions Cup

Manchester United 1999 treble winners voted best ever Premier League team over Liverpool, Arsenal Invincibles and Pep Guardiola's Man City side that won 100 points

1998–99 Manchester United F.C. season - Wikipedia

Legendary Teams: Manchester United's 1999 treble sparks the best stretch in the club's modern history - International Champions Cup

Manchester United, Sir Alex Ferguson and the 1999 Treble: That night in Barcelona - Eurosport

Legendary Teams: Manchester United's 1999 treble sparks the best stretch in the club's modern history - International Champions Cup

Manchester United, Sir Alex Ferguson and the 1999 Treble: That night in Barcelona - Eurosport

Can 2008 Manchester United beat 2019 Manchester City? - Quora