Nowak's paper is available here: sciencedirect.com/science/article/pii/0022314X89900188

@DerekHolt Your book is beautifully written! Thank you for recommending it!

@DerekHolt The class $\mathcal C_G$ for $G = SL_n(\mathbb F_q)$ is very explicit in Aschbacher's paper, but it's not clear to me what Aschbacher's main theorem actually says about subgroups that are not in $\mathcal C_G$, so perhaps the description is in Kleidman and Liebeck as Peter Mueller suggested.

@DerekHolt That's also my intuition, but do you know how one might prove it without going through Aschbacher's theorem?

Cooperstein's paper doesn't assume faithful.

Thank you, @DamianRössler. Scheider's paper is from 30 years ago. I was wondering if there are any more recent articles (post Voevodsky's works).

@FriedrichKnop Friedrich and Jason, thank you both for comments. Friedrich, what is a reference for the statement about the closure of P?