MLA
Hudtwalcker, Johannes Nicolaus. Letter from Johannes Nicolaus Hudtwalcker (Prussian Consulate in Savannah, Georgia) to Adjutant-General Henry Constantine Wayne Concerning the Drafting of Men under the Protection of the Prussian Consulate in Savannah - March 15, 1862. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 7, Folder 14. https://digital.library.emory.edu/purl/327mpg4g53-cor.
APA, 6th edition
Hudtwalcker, J. N. (1862). Letter from Johannes Nicolaus Hudtwalcker (Prussian Consulate in Savannah, Georgia) to Adjutant-General Henry Constantine Wayne concerning the drafting of men under the protection of the Prussian consulate in Savannah - March 15, 1862 (Box 7, Folder 14) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/327mpg4g53-cor.
Chicago
Hudtwalcker, Johannes Nicolaus. “Letter from Johannes Nicolaus Hudtwalcker (Prussian Consulate in Savannah, Georgia) to Adjutant-General Henry Constantine Wayne Concerning the Drafting of Men under the Protection of the Prussian Consulate in Savannah - March 15, 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/327mpg4g53-cor.