Acta Mathematica Sinica, English Series
Acta Mathematica Sinica, English Series > 2005 > 21 > 4 > 681-684
Acta Mathematica Sinica, English Series > 2005 > 21 > 4 > 681-684
Acta Mathematica Sinica, English Series > 2019 > 35 > 4 > 513-518
Acta Mathematica Sinica, English Series > 2005 > 21 > 4 > 681-684
Acta Mathematica Sinica, English Series > 2005 > 21 > 4 > 681-684
Acta Mathematica Sinica, English Series > 2019 > 35 > 4 > 513-518