Covering theorems for finite non-abelian simple groups, I J. L. Brenner, M. Randall, J. Riddell (1974) Colloquium Mathematicae
Covering theorems for finite nonabelian simple groups. III. - Solutions of the equation α x 2 + β t 2 + γ t - 2 = a in a finite field J. L. Brenner, L. Carlitz (1976) Rendiconti del Seminario Matematico della Università di Padova