中国科学院数学与系统科学研究院期刊网
A Spectrum Relation of Almost Periodic Solution of Second Order Scalar Functional Differential Equations with Piecewise Constant Argument
Li WANG, Rong YUAN, Chuan Yi ZHANG
Acta Mathematica Sinica . 2011, (11): 2275 -2284 .  DOI: 10.1007/s10114-011-8392-8