中国科学院数学与系统科学研究院期刊网
Multiplicity of Positive Solutions to Period Boundary Value Problems for Second Order Impulsive Differential Equations
Qiao-shu Zhou, Da-qing Jiang, Yu Tian
Acta Mathematicae Applicatae Sinica(English Series) . 2010, (1): 113 -124 .  DOI: 10.1007/s10255-007-7136-0