They are compatible, and it's right there in the core rules.
Very flavorful. Both the virtue and flaw suffer, imo, in that they are either extreme or insignificant, depending on whether a magus is able to take books to an appropriate environment.
But can't I have my apprentice copy the auram text so I can take that?
(That's what I mean. If a magus can never take a text from the library, the Flaw becomes "You are unable to study from texts." If a magus can easily do this, this becomes a Story Flaw.)
Well, it's meant to be a Hermetic Flaw. And, the Cow and Calf as described merely restricts the distribution of copies of the text, not the making of actual copies.
Sure, but you (usually) have to travel through the hurricane to get to it...
But for some character concepts it doesn't hurt that much. I have a Character with the Study Requirement flaw who focuses on making stuff with Rego Craft spells. Most of his spells are relatively low magnitude, and he's mastered them to boost his finesse. His few combat spells are indirect spells where he doesn't need to penetrate MR, so it hasn't really hurt him much yet because he hasn't needed high Art scores to accomplish what he wants to do. It will be a long time before he gets around to boosting his Arts high enough that the flaw becomes more than an inconvenience.
That's my point. If the requirement is trivial to get around, it's an awesome flaw to take, acting more like a Story Flaw for the few times it is going to matter. That's not necessarily a bad thing....
The payoff at Art scores 5-10 isn't bad, and if you are a young magus, a possible twilight episode might result in just as much beneficial knowledge, so not entirely madness.
The canonical cost of a sound tractatus is two pawns (Covenants, page 95), and goes up to three if you are in a rush. Although trading for other sound tractatus is common, too.