... King Fahd University of Petroleum andMinerals, Dhahran 31261, Saudi Arabia4Department of Mathematics, National University of Ireland, Galway, IrelandCorrespondence should be addressed to Haishen ... for Singular Boundary Value Problemswith Sign Changing and Superlinear NonlinearitiesHaishen L¨u,1Ravi P. Agarwal,2, 3and Donal O’Regan41Department of Applied Mathematics, Hohai University, ... 52−β,3.10Hindawi Publishing CorporationBoundary Value ProblemsVolume 2009, Article ID 103867, 34 pagesdoi:10.1155/2009/103867 Research Article An Approximation Approach to EigenvalueIntervals for...