1. F. E. Browder, Nonlinear eigenvalue problems and Galerkin approximations,Bull. Am. Math. Soc.,74 (1968), 651–656.
2. C. V. Coffman, An existence theorem for a class of non-linear integral equations with applications to a nonlinear elliptic boundary value problem,Journal of Math, and Mech.,18 (1968), 411–20.
3. —, On a class of non-linear elliptic boundary value problems, to appear.
4. R. E. Edwards,Functional Analysis, Holt Rinehart and Winston, Inc., New York, 1965.
5. M. A. Krasnosel’skii,Topological Methods in the Theory of Nonlinear Integral Equations, MacMillan, New York, 1964.