# Zassenhaus's theorem on sharply 3-transitive groups

I am looking for any modern (and English) reference to the following theorem:

If $$G$$ is finite group acting sharply $$3$$-transitively on $$1+2^m$$ points, then $$G \cong {\mathrm{PSL}}(2,2^m)$$.

I have looked at Huppert, Endliche Gruppen I, which seems to discuss the aspects on the converse direction (at least until chapter II) unless I am mistaken (my German is not too good). William Kerby's lecture note on "On infinite sharply multiply transitive groups" has it (Thm.10.2), however uses abstractions through skew fields.

I was wondering if there is a self contained proof without too much of details.