TY  - BOOK
AU  - Herrera, I.
TI  - perturbation method for elastic wave propagation. 1. nonpar-alell boundaries / I. Herrera
CY  - . : American Geophysical Union
N1  - "A reprinted from Journal of Geophysical Research. Volume 6-9, Number 18, September 15, 1964"
ER  -