中国科学院数学与系统科学研究院期刊网
AMS
The Average Widths of Sobolev-Wiener Classes and Besov-Wiener Classes
Gui Qiao XU, Yong Ping LIU
Acta Mathematica Sinica . 2004, (1): 81 -92 .  DOI: 10.1007/s10114-003-0247-5