Gaya APA

Rockville, . (1981). Results of Leveling Refraction Tests by the National Geodetic Survey (November 1981). United States of America: U.S Department of Commerce.

Gaya MLA

Rockville, . "Results of Leveling Refraction Tests by the National Geodetic Survey". November 1981 United States of America: U.S Department of Commerce, 1981. Text.