中国科学院数学与系统科学研究院期刊网
OSCILLATION OF EVEN ORDER NONLINEAR DIFFERENTIAL EQUATION WITH DEVIATING ARGUMENTS
Yan Shu-dong, He Xue-zhong
Acta Mathematicae Applicatae Sinica . 1992, (1): 136 -144 .  DOI: 10.12387/C1992015