Good resources for advanced English grammar?

[Oliwerko]

Hi folks.

I've been teaching English for a few years now, and some of my (one on one) students are becoming more and more advanced now. I'm used to working with grammar exercises, and the selection is quite good with intermediate English. Up to the B2 level, one can find tons of books and exercises around.

It becomes difficult with more advanced students. I don't really have any system of teaching the advanced, as I have with the elementary and intermediate students. I found this is largely because of unavailability of materials.

The question is: if you wanted to learn advanced English grammar, what book would you recommend? I'm mostly interested in exercises, the more the better, and the more mixed the better (i.e. all tenses in one exercise). I know the grammar, I just need exercises to do with my students.

Any tips? Also, if you have any pointers as to what a good approach to advanced students is, what techniques work with them, I'll be glad to hear them 

[Baron]

I feel bad that this topic has been neglected, especially since a good number of otherwise decent adventure games would benefit from at least a passing familiarity with advanced English grammar.  Also, I'd be interested in resources as well.  The only thing I can think of is Language Power published by Gage.  I used to use the earlier books quite a bit when I was a full time tutor (Language Power A, Language Power B), but it seems to me the series ran to D or E, and even C was challenging for my intermediates (mind you, they were the type of students who needed remedial tutoring....).  There were definitely lots of exercises though, which you could always stretch out (er... consolidate) with a writing exercise, etc.