00355nam a22000977a 4500 16270 16270 IS 10781:1984-Specification for Reference Coupler for the Measurement of Hearing Aids Using Earphones Coupled to The Ear by Means of Ear Inserts New Delhi : Bureau of Indian Standards (BIS), 1984. 7 p. Hearing aids ST 0 0 0 0 AIISH AIISH 2020-06-23 0 ST057 2020-06-23 00:00:00 2020-06-23 ST