1. The first and second boundary value problems for nonlinear second order differential equations;Bailey;J. Diff. Eq.,1966
2. Positivity and comparison results for nonlinear boundary value problems and related periodic solutions;Chandra;Tech. Rep. Watervliet Arsenal, WVT-6710,1967
3. Maximal solutions of mildly nonlinear elliptic equations;Parter,1966
4. Comparison of positive solutions of nonlinear equations;Chandra,1967
5. Positive Solutions of Operator Equations;Krasnoselskii,1964