MLA

John Young del, Lith. by A. Hoen & Co., Baltimore, Marylan. U.S.P.R.R. Exp. & Surveys-Cal. & Oregon. Botany-PlateVII. Abies williamsonii. Report of Lieut. Henry L. Abbotupon explorations for a railroad route, from the Sacramento Valley to the Columbia River, made by Lieut R. S. Williamson1855. Volume VI from Reports of explorations and surveys, to ascertain the most practicable and economi. ca. 1855. https://collections.library.yale.edu/catalog/2015735.

APA, 6th edition

John Young del, & Lith. by A. Hoen & Co., Baltimore, Marylan. (["Report of Lieut. Henry L. Abbotupon explorations for a railroad route, from the Sacramento Valley to the Columbia River, made by Lieut R. S. Williamson1855. Volume VI from Reports of explorations and surveys, to ascertain the most practicable and economi"])(ca. 1855)[U.S.P.R.R. Exp. & Surveys-Cal. & Oregon. Botany-PlateVII. Abies williamsonii]. https://collections.library.yale.edu/catalog/2015735.