TY  - JOUR
TI  - Methods of Theoretical Physics
AU  - Philip Μ. Morse
AU  - Herman Feshbach
AU  - E. L. Hill
PY  - 1954
JO  - American Journal of Physics
DO  - 10.1119/1.1933765
UR  - https://doi.org/10.1119/1.1933765
ER  -