However, there are some exotic pseudo-reductive algebraic groups over non-perfect fields whose construction is related to the construction of Ree groups, as they use the same exotic automorphisms of Dynkin diagrams that change root lengths.
Tits (1960) defined Ree groups over infinite fields of characteristics 2 and 3.
Tits (1989) and Hée (1990) introduced Ree groups of infinite-dimensional Kac–Moody algebras.
So this gives the finite Ree groups as subgroups of B2(22n+1), F4(22n+1), and G2(32n+1) fixed by an involution.
Ree realized that a similar construction could be applied to the Dynkin diagrams F4 and G2, leading to two new families of finite simple groups.
Wilson (2010) gave a simplified construction of the Ree groups, as the automorphisms of a 7-dimensional vector space over the field with 32n+1 elements preserving a bilinear form, a trilinear form, and a product satisfying a twisted linearity law.
Bombieri found out about this problem after reading an article about the classification by Gorenstein (1979), who suggested that someone from outside group theory might be able to help solving it.
Enguehard (1986) gave a unified account of the solution of this problem by Thompson and Bombieri.
Tits (1983) showed that all Moufang octagons come from Ree groups of type 2F4.