Oscillations of a class of second-order nonlinear delay differential equations with variable sign coefficients.

Jietao Zou Jianguo Zhang Xiaoyou Han Hongxia Zhu Oscillations of a class of second-order nonlinear delay differential equations with variable sign coefficients. 512-516 2007 SNPD (3) http://doi.ieeecomputersociety.org/10.1109/SNPD.2007.412 conf/snpd/2007 db/conf/snpd/snpd2007-3.html#ZouZHZ07