A note on cyclic semiregular subgroups of some 2-transitive permutation   groups
  We determine the semi-regular subgroups of the 2-transitive permutation groups PGL(2,n), PSL(2,n), PGU(3,n), PSU(3,n), Sz(n) and Ree(n) with n a suitable power of a prime number p. 
Massimo Giulietti, Gabor Korchmaros