2025-03-28https://repository.covenantuniversity.edu.ng/handle/123456789/34919We prove the existence of periodic solutions for the periodic boundary value problem (1.1) under some resonant conditions on the asymptotic behaviour of g(t, y) ay for |y| → ∞. The uniqueness of periodic solutions is also examinedapplication/pdfQA MathematicsON THE RESONANT OSCILLATION OF CERTAIN FOURTH ORDER NONLINEAR DIFFERENTIAL EQUATIONS WITH DELAYArticle