MLA
Walker, John Burns. Lithograph of Andersonville Prison (Georgia). “In June, July and August 1864, 33,000 Union Prisoners Were Crowded on…21 Acres," Sketched by John Burns Walker, Company G, 141st Regiment. T. Sinclairs Lith., 1864. Stuart A. Rose Manuscript, Archives, and Rare Book Library, OP10, Folder 5. https://digital.library.emory.edu/purl/389280gcc2-cor.
APA, 6th edition
Walker, J. B. (1864). Lithograph of Andersonville Prison (Georgia). “In June, July and August 1864, 33,000 Union prisoners were crowded on…21 acres," sketched by John Burns Walker, Company G, 141st Regiment (OP10, Folder 5) [Lithographs]. T. Sinclairs Lith.; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/389280gcc2-cor.
Chicago
Walker, John Burns. “Lithograph of Andersonville Prison (Georgia). ‘In June, July and August 1864, 33,000 Union Prisoners Were Crowded on…21 Acres," Sketched by John Burns Walker, Company G, 141st Regiment.” Lithographs. Civil War Collection. Philadelphia, PA: T. Sinclairs Lith., 1864. OP10, Folder 5. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/389280gcc2-cor.