Contributions to the theory of partial differential equations / by S. Bergman [and others] edited by L. Bers, S. Bochner, and F. John. Bers, Lipman, ed. Bergman, Stefan, 1898-1977. Differential equations, Partial. QA371 .B46 517.38 BEC "Papers ... read at the Conference on Partial Differential Equations, sponsored by the National Academy of Sciences, National Research Council, October 1952." Includes bibliographies. Princeton : Princeton University Press, 1954. 1954. 1954 Text v, 257 p. ; eng Annals of mathematics studies, no. 33