1. Agarwal R P 1977J. Math. Phys. Sci. (to appear)
2. Bernfeld S R and Lakshmikantham V 1974An Introduction to nonlinear boundary value problems (New York: Academic Press).
3. McGill R and Kenneth P 1963Astronaut. Cong. Paris IV
12 173
4. Roberts S M and Shipman J S 1972Two-point boundary value problems: Shooting methods (New York: American Elsevier)
5. Urabe M 1973Mem. Fac. Sci., Kyushu Univ.
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