中国科学院数学与系统科学研究院期刊网
Existence Theorems for Periodic Differential Inclusions in I\!R$^{\hbox{$^N$}}$
Michael Filippakis, Leszek Gasinski, Nikolaos S. Papageorgiou
Acta Mathematicae Applicatae Sinica(English Series) . 2004, (2): 179 -190 .