We're the best, f*ck you': The story of Barca & Real's four Clasicos in 18 days
Messi: My rivalry with Ronaldo 'will be remembered forever' — RT Sport News
Five times Messi and Ronaldo left their mark on the El Clasico
Barcelona, Real Madrid: Oral history of four clasicos in 18 days - ESPN
WATCH: Lionel Messi's first ever El Clasico - Sportstar
Messi: I miss Ronaldo in La Liga - Sportstar
El Clásico Preview: What's greater?: Real Madrid's threat or Barcelona's execution? - Barca Blaugranes
Why is Messi better than Ronaldo? - Quora
Real Madrid 2-3 Barcelona: El Clásico – as it happened, La Liga
Barcelona, Real Madrid and El Clasico The people who made it the biggest match in soccer - ESPN
Real Madrid 0-3 Barcelona: El Clásico – as it happened, La Liga