APA (7th ed.) Citation

U.S. Coast and Geodetic Survey. (1921). General tide tables for year 1921. GPO.

Chicago Style (17th ed.) Citation

U.S. Coast and Geodetic Survey. General Tide Tables for Year 1921. [Washington]: GPO, 1921.

MLA (9th ed.) Citation

U.S. Coast and Geodetic Survey. General Tide Tables for Year 1921. GPO, 1921.