中国科学院数学与系统科学研究院期刊网
AMS
Convex Functions, Subdifferentiability and Renormings
Cheng Lixin, Wu Congxin, Xue Xiaoping, Yao Xiaobo
Acta Mathematica Sinica . 1998, (1): 47 -56 .  DOI: 10.1007/BF02563883