TY  - RPRT
TI  - Circular of the Bureau of Standards no. 439: acoustic performance of 16-millimeter sound motion-picture projectors
AU  - Snyder, Wilbert F
PY  - 1942
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS CIRC 439
DO  - 10.6028/NBS.CIRC.439
ER  -