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2. W. J. Shi, “A characteristic property ofPSL 2(7),”J. Austr. Math. Soc., Ser. A,36, No. 3, 354–356 (1984).
3. W. J. Shi, “A characterization of some projective special linear groups,”J. Southwest-China Teachers Univ., Ser. B., No. 2, 2–10 (1985).
4. W. J. Shi, “A characteristic property ofJ 1 andPSL 2(2 n ),”Adv. Math. Beijing,16, No. 4, 397–401 (1987).
5. R. Brandl and W. J. Shi, “The characterization ofPSL(2,q) by its element orders,”J. Alg.,163, No. 1, 109–114 (1994).