TY  - RPRT
TI  - Measurement of the setting time and strength of concrete by the impact-echo method 
AU  - Pessiki, Stephen P
AU  - Carino, Nicholas J
PY  - 1987
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS IR 87-3575
DO  - 10.6028/NBS.IR.87-3575
ER  -