One succinct version of Bender's method is the result that if M, N are two distinct maximal subgroups of a simple group with F*(M) ≤ N and F*(N) ≤ M, then there is a prime p such that both F*(M) and F*(N) are p-groups. This situation occurs whenever M and N are distinct maximal parabolic subgroups of a simple group of Lie type, and in this case p is the characteristic, but this has only been used to help identify groups of low Lie rank. These ideas are described in textbook form in Gagen (1976, p. 43),
Huppert & Blackburn (1982, Chapter X. 15), Gorenstein, Lyons & Solomon (1996, p. 110, Chapter F.19), and Kurzweil & Stellmacher (2004, Chapter 10.1).