American National Standard for Preferred Earhook Nozzle Thread for Postauricular Hearing Aids
standard by American National Standards of the Acoustical Society of America, 04/28/1987

American National Standard Methods to Define and Measure the Residual Sound in Protected Natural and Quiet Residential Areas
standard by American National Standards of the Acoustical Society of America, 12/05/2014

American National Standard Electroacoustics - Simulators of Human Head and Ear - Part 5: 2 cm*2 Coupler for the Measurement of Hearing Aids and Earphones Coupled to the Ear by Means of Ear Inserts (a modified nationally adopted international standard)
standard by American National Standards of the Acoustical Society of America, 07/21/2014