中国科学院数学与系统科学研究院期刊网
PERIODIC SOLUTIONS OF THE DUFFING EQUATION WITH DELAYS AND IMPULSES
Jian Li LI, Jian Hua SHEN
Acta Mathematicae Applicatae Sinica . 2005, (1): 124 -133 .  DOI: 10.12387/C2005012