1. H. Wise andC. M. Ablow:Journ. Chem. Phys.,35, 10 (1961).
2. P. B. Bailey, L. F. Shampine andP. E. Waltman:Nonlinear Two-Point Boundary Value Problems (New York, 1968), p. 116.
3. A. M. Arthurs:Complementary Variational Principles (Oxford, 1970).
4. A. M. Arthurs andC. W. Coles:Journ. Inst. Math. Appl.,7, 324 (1971).
5. A. M. Arthurs:Journ. Math. Anal. Appl., in press (1972).