Hello friends!
I started solving Sudokus some days ago, after solving some harder ones I finally found one that I cant easily finish :
http://i.imgur.com/1AvyHno.png
Don't get confused by my exclamation marks, it's just my habit to signalize 2-candidate-only fields like that.
Are the 3 fields I marked with the circle a xyz-wing? If no, how can I solve the Sudoku?
Thanks in advance!