Acta Mathematica Sinica, English Series
Acta Mathematica Sinica, English Series > 2004 > 20 > 2 > 247-254
Acta Mathematica Sinica, English Series > 2004 > 20 > 2 > 247-254
Acta Mathematica Sinica, English Series > 2004 > 20 > 3 > 423-432
Acta Mathematica Sinica, English Series > 2004 > 20 > 2 > 247-254
Acta Mathematica Sinica, English Series > 2004 > 20 > 2 > 247-254
Acta Mathematica Sinica, English Series > 2004 > 20 > 3 > 423-432