MLA

Ledyard, Edgar M. (Edgar Madison), b. 1875. Gidex for Utah / data compiled by Edgar M. Ledyard ; map drawn by Elwood B. Stockman ; compiled by Utah Historical Landmarks Association.. BRBL_00593. c1928.. https://collections.library.yale.edu/catalog/15818511.

APA, 6th edition

Ledyard, Edgar M. (Edgar Madison), b. 1875. (["BRBL_00593"])(c1928.)[Gidex for Utah / data compiled by Edgar M. Ledyard ; map drawn by Elwood B. Stockman ; compiled by Utah Historical Landmarks Association.]. https://collections.library.yale.edu/catalog/15818511.