Hearing aids.

Author/creator Corliss, Edith L. R.
Format Book
Publication InfoWashington : For sale by the Supt. of Docs., U.S. Govt. Print. Off, 1970.
Descriptioniv, 24 pages : illustrations ; 27 cm.
Subjects

SeriesNational Bureau of Standards monograph 117
NBS monograph ; 117. ^A329613
General noteSupersedes the Bureau's Circular 534.
LCCN 74606242
Govt. docs number C 13.44:117