TY  - RPRT
TI  - Letter Circular 344: sound absorption coefficients of the more common materials (superseding Letter Circular 326)
PY  - 1932
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 344
DO  - 10.6028/NBS.LCIRC.344
ER  -