[1] Aftabizadeh, A. R.: 
Existence and uniqueness theorems for fourth-order boundary value problems. J. Math. Anal. Appl. 116 (1986), 415–426. 
MR 0842808 | 
Zbl 0634.34009 
[2] Agarwal, R.: 
On fourth-order boundary value problems arising in beam analysis. Differ. Integral Equ. 2 (1989), 91–110. 
MR 0960017 | 
Zbl 0715.34032 
[3] Bressan, A. and Colombo, G.: 
Extensions and selections of maps with decomposable values. Studia Math. 90 (1988), 69–86. 
MR 0947921 
[3] Cabada, A.: 
The method of lower and upper solutions for second, third, fourth, and higher order boundary value problem. J. Math. Anal. Appl. 248 (2000), 195–202. 
MR 1283059 
[5] Castaing, C. and Valadier, M.: 
Convex Analysis and Measurable Multifunctions. Lecture Notes in Mathematics, vol. 580, Springer-Verlag, Berlin-Heidelberg-New York, 1977. 
MR 0467310 
[6] Covitz, H. and Nadler, S. B., Jr.: 
Multivalued contraction mappings in generalized metric spaces. Israel J. Math. 8 (1970), 5–11. 
MR 0263062 
[7] De Coster, C., Fabry, C. and Munyamarere, F.: 
Nonresonance condition for fourth-order nonlinear boundary value problems. Int. J. Math. Math. Sci. 17 (1994), 725–740. 
MR 1298797 
[9] Del Pino, M. A. and Manasevich, R. F.: 
Existence for a fourth-order boundary value problem under a two-parameter nonresonance condition. Proc. Amer. Math. Soc. 112 (1991), 81–86. 
MR 1043407 
[10] Frigon, M. and Granas, A.: 
Théorèmes d’existence pour des inclusions différentielles sans convexité. C. R. Acad. Sci. Paris, Ser. I Math. 310 (1990), 819–822. 
MR 1058503 
[11] Gorniewicz, L.: 
Topological Fixed Point Theory of Multivalued Mappings. Math. Appl. 495, Kluwer Academic Publishers, Dordrecht, 1999. 
MR 1748378 | 
Zbl 1107.55001 
[12] Hu, Sh. and Papageorgiou, N.: 
Handbook of Multivalued Analysis, Volume I: Theory. Kluwer Academic Publishers, Dordrecht, Boston, London, 1997. 
MR 1485775 
[13] Kisielewicz, M.: 
Differential Inclusions and Optimal Control. Kluwer, Dordrecht, The Netherlands, 1991. 
MR 1135796 | 
Zbl 0731.49001 
[14] Korman, P.: 
A maximum principle for fourth-order ordinary differential equations. Appl. Anal. 33 (1989), 267–273. 
MR 1030113 | 
Zbl 0681.34016 
[15] Ma, R. Y., Zhang, J. H. and Fu, M.: 
The method of lower and upper solutions for fourth-order two-point boundary value problem. J. Math. Anal. Appl. 215 (1997), 415–422. 
MR 1490759 
[16] Schroeder, J.: 
Fourth-order two-point boundary value problems; estimates by two-sided bounds. Nonlinear Anal. 8 (1984), 107–114. 
MR 0734445 | 
Zbl 0533.34019 
[18] Švec, M.: 
Periodic boundary value problem for fourth order differential inclusions. Arch. Math. (Brno) 33 (1997), 167–171. 
MR 1464311