Powers, D. L. (1979). Boundary value problems (2a. ed.). Academic.
Cita Chicago (17th ed.)Powers, David L. Boundary Value Problems. 2a. ed. Nueva York: Academic, 1979.
Cita MLA (9th ed.)Powers, David L. Boundary Value Problems. 2a. ed. Academic, 1979.
Atenció: Aquestes cites poden no estar 100% correctes.