TY  - RPRT
TI  - Sonic impedance technique detects flaws in polyurethane foam spray-on insulation
AU  - Haralson, H. S.
AU  - Haynes, J. L.
PY  - 1970
UR  - https://ntrs.nasa.gov/citations/19700000012
ID  - 19700000012
ER  -