TY  - RPRT
TI  - Letter Circular 49: description and operation of an audio-frequency amplifier unit for simple radio receiving outfits
PY  - 1922
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 49
DO  - 10.6028/NBS.LCIRC.49
ER  -