Existence theorem of periodic positive solutions for the Rayleigh equation of retarded type. Wang, Genqiang; Yan, Jurang — 2000 Portugaliae Mathematica
Existence of periodic solution for first order nonlinear neutral delay equations. Wang, Genqiang; Yan, Jurang — 2001 Journal of Applied Mathematics and Stochastic Analysis
On existence of periodic solutions of the Rayleigh equation of retarded type. Wang, Genqiang; Yan, Jurang — 2000 International Journal of Mathematics and Mathematical Sciences