中国科学院数学与系统科学研究院期刊网
The Unique Existence of Almost Periodic Solutions for the System of Differential Equations with Piecewise Constant Argument
Xi Tao YANG
Acta Mathematica Sinica, Chinese Series . 2007, (2): 461 -472 .  DOI: 10.12386/A2007sxxb0054