TY  - BOOK
AU  - Heading,J., x
AU  - x
TI  - An Introduction to phase-integral methods: x
SN  - x
U1  - 517.3/HEI 
PY  - 1962///
CY  - London
PB  - Wiley
KW  - Waves
KW  - Mathematical Physics
N1  - x
ER  -