Those don't look like Ronaldo's autograph to me, but hopefully others will comment.
A very reliable source for Ronaldo's autograph is Icons: http://www.icons.com/players/l-z/cristiano-ronaldo-signed-memorabil...
Thanks for your reply Steve, I have in fact an unusual story behind this if it helps...
I got these 4 jerseys signed by at the Intercontinental Budapest last Saturday night after the practice for the match against Hungary.
I am a Portugal native and could get to the National Coach and other members and players of the squad and after asking, I had to leave my bag with a member of the Portuguese National Team that then went up to him and brought them back to me whilst I was waiting in the 1st floor with Quaresma, Bruno Alves, Fabio Coentrao and Eliseu.
But again I did not saw him sign.
Does this make any difference? Or does someone else signs it for him?
Cheers and thanks
It could be that someone else signed for him, since you didn't see them signed. That's not unusual unfortunately in sports, entertainment or music.
Click the link I posted to his signed items at Icons.com and see how the autographs compare to theirs.
Others here may have a different opinion than I do, though.
When he played for man Utd someone else USED to sign for him via ttm brother or cousin but with your story being Portuguese surprised he didn't sign it but have to say not to keen on this one
You can contact Garry King at Autografica in the UK. He's a member here, and a UK-based authenticator who is very good in international football: