I am looking for a grammar book or series of grammar books for Spanish that match the following criteria:
- the book or books must be in Spanish, i.e. all grammar rules and instructions must be in Spanish (not English, German, French, ...);
- content should be organised in chapters that first explain a set of grammar rules and then provide a number of exercises that apply these rules;
- there must be an answer key (the answer key may be a separate volume);
- the book must be appropriate for self study (the presence of an answer key is not sufficient; some books of this type are intended for teachers of Spanish).
I am looking for books for the levels A2 - B2. The first three criteria may be easy to fulfil, but the last criterion is essential and it may not be obvious whether a book matches this criterion just by looking at the book cover in an online bookshop. Answers that are based on personal experience using such books would be especially appreciated.