TY  - RPRT
TI  - Detection of human intruders by low frequency sonic interferometric techniques 
AU  - Stoltenberg, Robert E
PY  - 1974
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS IR 74-364
DO  - 10.6028/NBS.IR.74-364
ER  -