中国科学院数学与系统科学研究院期刊网
AMS
The Answer to a Problem Posed by Zhao and Ho
Bin ZHAO, Jing LU, Kai Yun WANG
Acta Mathematica Sinica . 2019, (3): 438 -444 .  DOI: 10.1007/s10114-018-7535-6