... CorporationBoundary Value ProblemsVolume 2011, Article ID 569191, 13 pagesdoi:10.1155/2011/569191 Research Article A Fourth-Order Boundary Value Problem with One-Sided Nagumo ConditionWenjing Song1, ... Cabada, “An overview of the lower and upper solutions method with nonlinear boundary valueconditions,” Boundary Value Problems, vol. 2011, Article ID 893753, 18 pages, 2011.16 M. R. Grossinho, ... Value ProblemsTherefore, Fλsatisfies the one-sided Nagumo-type condition in Er1 with hEreplaced by hEr1, with r1independent of λ ∈ 0, 1.Moreover, forρ : maxar1|A|b,|B|...