The clause that could let Cristiano Ronaldo leave Al Nassr and play Champions League again
El Clasico: Lionel Messi & Cristiano Ronaldo absent - who can light up El Clasico? - BBC Sport
Lionel Messi vs Cristiano Ronaldo: Champions League records compared
Lionel Messi and Cristiano Ronaldo are 'All-In' for El Clasico at Camp Nou - Barca Blaugranes
Lionel Messi vs Cristiano Ronaldo: World Cups, quick hat-tricks and Emile Heskey's scoring feats — 11 records Barcelona and Real Madrid stars have NOT broken
Full list of Champions League records held by Messi and Ronaldo
Lionel Messi and Cristiano Ronaldo's staggering Champions League records and honours as Juve ace nets brace vs Lyon
18 Champions League Records Not Held By Lionel Messi Or Cristiano Ronaldo - SPORTbible
World's top two soccer players are missing something - Los Angeles Times