Reference for the subgroup structure of $\rm{PSL}_2(q)$ This material is covered in detail in Dickson's "Linear Groups with an exposition of the Galois Field Theory", chapter XXII and Huppert's "Endliche Gruppen", chapter II, paragraph 8. Since I don't speak german and Dickson's treatment often requires deciphering, I was wondering if there is a "modern" account of this somewhere.
 A: Suzuki's Group Theory (I) 3.§6 page 392-418 is modern and very clear.  The main theorem is on page 404, which coincidentally is the error code from google books for its page scan.
A: Two other modern references for the maximal subgroups of ${\rm PSL}(2,q)$ are:  Bray, Holt and Roney-Dougal, The maximal subgroups of the low-dimensional finite classical groups, London Mathematical Society Lecture Note Series, vol. 407, 2013, and Michael Giudici, Maximal subgroups of almost simple groups with socle ${\rm PSL}(2,q)$, arXiv:math/0703685.
A: It's also covered in Gorenstein's Finite Groups (ironically enough, also in section 8 of chapter 2, just like Huppert, but I think this is coincidence).
A: There are some notes by Oliver King containing a statement of the full classification in modern terms.  However, this expository paper does not derive the result.  A standard reference for the subgroup structure of classical groups is the book by Kleidman and Liebeck, but I don't recall that they cover Dickson's full list.  They focus on maximal subgroups.  The exposition there is rather, shall we say, "efficient".
A: B. Huppert, Endliche Gruppen I, Springer, Berlin, 1967.
