This paper deals with the periodic solutions of a class of fourth-order superlinear differential equations. By using the classical variational techniques and symmetric mountain pass lemma, the periodic solutions of a single equation in literature are extended to that of equations, and also, the cubic growth of nonlinear term is extended to a general form of superlinear growth.
"Periodic Solutions of a Class of Fourth-Order Superlinear Differential Equations." Abstr. Appl. Anal. 2012 (SI07) 1 - 8, 2012. https://doi.org/10.1155/2012/469863