On abelian separable extensions and Galois sets of rings G. Szeto; Linjun Ma — 1989 Matematički Vesnik
On Galois projective group rings. Szeto, George; Ma, Linjun — 1991 International Journal of Mathematics and Mathematical Sciences
On rings whose centers are Galois extensions Szeto, George; Ma, Linjun — 1988 Portugaliae mathematica