MLA
Hudtwalcker, Johannes Nicolaus. Letter from Johannes Nicolaus Hudtwalcker (Prussian Consulate in Savannah, Georgia)to Joseph E. Brown, Governor of Georgia, Concerning the Drafting of Men under the Protection of the Prussian Consulate in Savannah - March 11, 1862. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 7, Folder 14. https://digital.library.emory.edu/purl/040xpnvz25-cor.
APA, 6th edition
Hudtwalcker, J. N. (1862). Letter from Johannes Nicolaus Hudtwalcker (Prussian Consulate in Savannah, Georgia)to Joseph E. Brown, Governor of Georgia, concerning the drafting of men under the protection of the Prussian consulate in Savannah - March 11, 1862 (Box 7, Folder 14) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/040xpnvz25-cor.
Chicago
Hudtwalcker, Johannes Nicolaus. “Letter from Johannes Nicolaus Hudtwalcker (Prussian Consulate in Savannah, Georgia)to Joseph E. Brown, Governor of Georgia, Concerning the Drafting of Men under the Protection of the Prussian Consulate in Savannah - March 11, 1862.” Letters (correspondence). Civil War Collection, 1862. Box 7, Folder 14. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/040xpnvz25-cor.