TY  - RPRT
TI  - FM-CW electromagnetic technique of measuring coal layer thickness 
AU  - Ellerbruch, Doyle A
AU  - Belsher, Donald R
PY  - 1976
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS IR 76-840
DO  - 10.6028/NBS.IR.76-840
ER  -