Positive radial solutions of a singular elliptic equation with sign changing nonlinearities

Coclite, 1989, On a singular nonlinear Dirichlet problems, Comm. Partial Differential Equations, 14, 1315, 10.1080/03605308908820656 Cui, 2000, Existence and nonexistence of positive solutions for singular semilinear elliptic boundary value problems, Nonlinear Anal., 41, 149, 10.1016/S0362-546X(98)00271-5 Fink, 1991, Approximation of solutions of singular second-order boundary value problems, SIAM J. Math. Anal., 22, 440, 10.1137/0522029 Baxley, 1991, Some singular nonlinear boundary value problems, SIAM J. Math. Anal., 22, 463, 10.1137/0522030 Usami, 1989, On a singular elliptic boundary value problem in a ball, Nonlinear Anal., 13, 1163, 10.1016/0362-546X(89)90004-7 Habets, 1994, Upper and lower solutions for a generalized Emden–Fowler equation, J. Math. Anal. Appl., 181, 684, 10.1006/jmaa.1994.1052 Agarwal, 2003