Comparison of speech intelligibility in cockpit noise using SPH-4 flight helmet with and without active noise reduction [electronic resource] / Jeffrey W. Chan and Carol A. Simpson.
Imprint
Menlo Park, Calif. : DEV AIR Technical Associates ; Moffett Field, Calif. : National Aeronautics and Space Administration, Ames Research Center ; [Springfield, Va. : For sale by the National Technical Information Service, 1990]
