[1] Agarwal R.P., O'Regan D., Wong P.J.Y.: 
Positive Solutions of Differential, Difference and Integral Equations. Kluwer, Dordrecht, 1999. 
Zbl 1157.34301[2] Benchohra M., Hamani S., Henderson J., Ntouyas S.K., Ouahab A.: 
Positive solutions for systems of nonlinear eigenvalue problems. Global J. Math. Anal. 1 (2007), 19-28. 
MR 2374098[4] Graef J.R., Yang B.: 
Boundary value problems for second order nonlinear ordinary differential equations. Commun. Appl. Anal. 6 (2002), 273-288. 
MR 1894171 | 
Zbl 1085.34514[5] Guo D., Lakshmikantham V.: 
Nonlinear Problems in Abstract Cones. Academic Press, Orlando, 1988. 
MR 0959889 | 
Zbl 0661.47045[6] Henderson J., Ntouyas S.K.: 
Positive solutions for systems of nonlinear boundary value problems. Nonlinear Studies, in press. 
Zbl 1148.34016[7] Henderson J., Ntouyas S.K.: 
Positive solutions for systems of three-point nonlinear boundary value problems. Austr. J. Math. Anal. Appl., in press. 
MR 2413225[12] Infante G.: 
Eigenvalues of some nonlocal boundary value problems. Proc. Edinburgh Math. Soc. 46 (2003), 75-86. 
MR 1961173[14] Liang R., Peng J., Shen J.: 
Positive solutions to a generalized second order three-point boundary value problem. Appl. Math. Comput. (2007) doi:10.1016/j.amc.2007.07.025. 
Zbl 1140.34313[16] Raffoul Y.: 
Positive solutions of three-point nonlinear second order boundary value problems. Electron. J. Qual. Theory Differ. Equ. 2002, no. 15, 11pp. (electronic). 
MR 1934391