Propelled lighter-than-air vehicles : hearings before the Subcommittee on Science, Technology, and Space of the Committee on Commerce, Science, and Transportation, Ninety-sixth Congress, first session ... February 27 and March 1, 1979.
United States.Congress.Senate.Committee on Commerce, Science, and Transportation.Subcommittee on Science, Technology, and Space.
Washington : U.S. Govt. Print. Off.,
1979.
"Serial no. 96-6."
Airships.
Helicopters.