Brauer-Feit theorem

Staement
There exists a function $$f: \mathbb{N} \times \mathbb{N} \to \mathbb{N}$$ such that the following holds. If $$G$$ is a finite group embedded in a group $$GL(n,K)$$ where $$K$$ has characteristic $$p$$ and $$P$$ is a $$p$$-Sylow subgroup of $$G$$, there exists an abelian subgroup of $$G$$ whose index is at most $$f(n,|P|)$$.