... problems,” inHandbook of Differential Equations, pp. 69–160, Elsevier/North-Holland, Amsterdam, The Netherlands,2004.14 C. De Coster and P. Habets, An overview of the method of lower and upper ... Value Problems 3In the classical books of Bernfeld and Lakshmikantham 6 and Ladde et al. 7 theclassical theory of the method of lower and upper solutions and the monotone iterativetechnique ... Problems: Lower and Upper Solutions, vol. 205 of Mathematics in Science and Engineering, Elsevier, Amsterdam, The Netherlands, 2006.13 C. De Coster and P. Habets, “The lower and upper solutions...