I just came across a website offering books for Fiddle and Mandolin on a shareware basis.
That is you can watch and use the books and if you find it useful contribute 10$ each to the owner. That's really fair. I think, one or two of the books might be of interest for players of the bouzouki, too. Especially the one dealing with double stop runs.
You can find this one here:
Here's also a video from the website: