TY  - RPRT
TI  - Zonal harmonics in low frequency terrestrial radio wave propagation. 
AU  - Johler, J Ralph
PY  - 1966
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS TN 335
DO  - 10.6028/NBS.TN.335
ER  -