Which books do you recommend to prepare for the exams CELI (or CILS) ?
I would like to train for the C1 level. I see that this reference book seems to be expired : https://www.guerra-edizioni.com/books/index.cfm?node=0,1,22,1006,168,1175.
What would you recommend ? Alternatively, strong online resources.
I tend to favor CELI because there is preparation and exam center in my city / country. Would you recommend otherwise ? What is the most challenging, the most recognized exam ?