TY - GEN AU - Heyl, Paul R C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1931-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.CIRC.396 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1931 TI - Circular of the Bureau of Standards no. 396::architectural acoustics ER -