TY - BOOK T1 - Helicopter acoustics :proceedings of an International Specialists Symposium sponsored by the American Helicopter Society, Washington, D.C.; the U.S. Army Research Office, Durham, North Carolina; and the Langley Research Center, Hampton, Virginia, and held at Langley Research Center, May 22-24, 1978. DA - 1978. CY - [Washington] : CY - Springfield, Va. : CN - NAS 1.55: PB - National Aeronautics and Space Administration, Scientific and Technical Information Office ; PB - for sale by the National Technical Information Service, PP - [Washington] : PP - Springfield, Va. : PY - 1978. ID - 180249 KW - Helicopters KW - Acoustical engineering KW - Noise control TI - Helicopter acoustics :proceedings of an International Specialists Symposium sponsored by the American Helicopter Society, Washington, D.C.; the U.S. Army Research Office, Durham, North Carolina; and the Langley Research Center, Hampton, Virginia, and held at Langley Research Center, May 22-24, 1978. ER -