APA (7th ed.) Citation

U.S. Coast and Geodetic Survey. (1921). Results of observations made at U.S. Coast and Geodetic Survey magnetic observatory at Cheltenham, Md. in 1921 and 1922. GPO.

Chicago Style (17th ed.) Citation

U.S. Coast and Geodetic Survey. Results of Observations Made at U.S. Coast and Geodetic Survey Magnetic Observatory at Cheltenham, Md. in 1921 and 1922. [Washington]: GPO, 1921.

MLA (9th ed.) Citation

U.S. Coast and Geodetic Survey. Results of Observations Made at U.S. Coast and Geodetic Survey Magnetic Observatory at Cheltenham, Md. in 1921 and 1922. GPO, 1921.