APA (7th ed.) Citation

United States. National Advisory Committee for Aeronautics. (1937). Sound pressure-level meter without amplification. [s.n.].

Chicago Style (17th ed.) Citation

United States. National Advisory Committee for Aeronautics. Sound Pressure-level Meter Without Amplification. [Washington]: [s.n.], 1937.

MLA (9th ed.) Citation

United States. National Advisory Committee for Aeronautics. Sound Pressure-level Meter Without Amplification. [s.n.], 1937.