Hearing aids
Series: [U. S.] National Bureau of Standards. Circular -- 534; National Bureau of Standards circular -- 534.
Publisher: U. S. Govt. Print. Off.
Published: 1953
Place of publication: Washington
Language: eng
Number of pages: 18
Subjects: Hearing Aids
Notes: Issued as revision of the Bureau's Circular 516 with title: Selection of hearing aids.