1[1]Thandapani E, Pandian S. Asymptotic and oscillatory behavior of solutions of general nonlinear difference equations of second order[J]. Computer Math Appl,1998,36(10-12), 413-421
2[2]Rogovchenko Y V. Oscillation criteria for certain nonlinear differential equations[J]. J Math Anal Appl,1999(229):399-461
3[3]Grace S R. Oscillation criteria for certain nonlinear differential equations[J]. Math Anal Appl,1992(171):220-241
4[4]Kuang J C. Common Inequalities[M]. Changsha: Hunan Education Press, 1989
3[1]WAZEWSKA-CZYZEWSKA M,LASOTA A.Mathematical problems of the dynamics of a system of red blood cells[J].Mat Stos.1976,6:23-40.
4[2]LI J W,WANG Z C.Existence and global attractivity of positive periodic solutions of a survival model of red blood cells[J].Computers Math Applic.2005,50:41-47.
5[6]ZENG Z J,BI L,FAN M.Existence of multiple positive periodic solutions for functional differential equations[J].J.Math.Anal.Appl.2007,325:1378-1389.
6[7]GAINES R E,MAWHIN J L.Coincidence Degree and Nonlinear Differential Equations[M].Springer,Berlin,1997.