一类具有反馈控制项时滞泛函差分系统的周期正解
郭鹏飞, 朱先阳, 李永昆
Two Positive Periodic Solutions of Delay Functional Difference System with Feedback Control 
GUO Peng-fei, ZHU Xian-yang, LI Yong-kun
数学季刊 . 2009, (1): 102 -107 .