MLA
Gourdin, Martha. Drawing by Martha Gourdin, Wife of Confederate General Wilmot Gibbes De Saussure, of Confederate State Flags. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 3. https://digital.library.emory.edu/purl/064tht77hq-cor.
APA, 6th edition
Gourdin, M. Drawing by Martha Gourdin, wife of Confederate General Wilmot Gibbes De Saussure, of Confederate state flags (Box 3, Folder 3) [Drawings (visual works)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/064tht77hq-cor.
Chicago
Gourdin, Martha. “Drawing by Martha Gourdin, Wife of Confederate General Wilmot Gibbes De Saussure, of Confederate State Flags.” Drawings (visual works). Civil War Collection, n.d. Box 3, Folder 3. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/064tht77hq-cor.