The following publications are possibly variants of this publication:
- Existence of positive periodic solutions for a class of functional differential equationsYan Sun, Maoan Han, Lokenath Debnath. amc, 190(1):699-704, 2007. [doi]
- Positive periodic solutions for neutral functional differential equationsWeibing Wang, Jianhua Shen. appml, 102:106154, 2020. [doi]
- Three Positive Periodic Solutions to Nonlinear Neutral Functional Differential Equations with Parameters on Variable Time ScalesYongkun Li, Chao Wang. jam, 2012, 2012. [doi]
- Three positive periodic solutions to nonlinear neutral functional differential equations with impulses and parameters on time scalesChao Wang, Yongkun Li, Yu Fei. mcm, 52(9-10):1451-1462, 2010. [doi]