Powers, D. L. (1987). Boundary value problems (3rd ed.). Harcourt Brace Jovanovich.
Dyfyniad Arddull ChicagoPowers, David L. Boundary Value Problems. 3rd ed. San Diego: Harcourt Brace Jovanovich, 1987.
Dyfyniad MLAPowers, David L. Boundary Value Problems. 3rd ed. Harcourt Brace Jovanovich, 1987.
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