TY  - RPRT
TI  - Nondestructive test to determine concrete strength- a status report 
AU  - Clifton, James R
PY  - 1975
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS IR 75-729
DO  - 10.6028/NBS.IR.75-729
ER  -