共 9 条
- [1] COURANT R, 1953, METHODS MATH PHYSICS, V1
- [2] Duffin R. J., 1960, Q APPL MATH, V18, P215
- [3] DUFFIN RJ, 1955, J RATION MECH ANAL, V4, P221
- [4] Fischer E., 1905, MONATSH F MATH PHYSI, V16, P234
- [5] MORSE M, 1938, MEM SCI MATH, V92
- [6] Poincare H., 1890, AM J MATH, V12, P211, DOI 10.2307/2369620
- [7] RAYLEIGH, SCI PAPERS, V1, P170
- [8] Rayleigh L., 1873, P LOND MATH SOC, V4, P357