TY  - RPRT
TI  - Nondestructive evaluation methods for quality acceptance of hardened concrete in structures 
AU  - Clifton, James R
AU  - Anderson, Erik D
PY  - 1981
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS IR 80-2163
DO  - 10.6028/NBS.IR.80-2163
ER  -