Ahlème Bouakkaz, Abdelouaheb Ardjouni, Rabah Khemis, Ahcene Djoudi
abstract:
The purpose of this work is to establish and study some useful properties of 
Green's functions of the fourth-order linear differential equation before using 
them together with the Guo-Krasnosel'skiǐ's fixed point theorem for proving the 
existence of positive periodic solutions of the fourth-order nonlinear 
differential equation.
Mathematics Subject Classification: Primary 34K13, 34A34; Secondary 34K30, 34L30
Key words and phrases: Positive periodic solutions, nonlinear differential equations, fixed point theorem, Green's function