MLA
Smeltzer, John. Letter from John Smeltzer (West Hanover Township, Dauphin County, Pennsylvania) to W. F. Landis, Regarding Farming - April 25, 1869. 1869. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 9, Folder 29. https://digital.library.emory.edu/purl/044bnzs8m0-cor.
APA, 6th edition
Smeltzer, J. (1869). Letter from John Smeltzer (West Hanover Township, Dauphin County, Pennsylvania) to W. F. Landis, regarding farming - April 25, 1869 (Box 9, Folder 29) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/044bnzs8m0-cor.
Chicago
Smeltzer, John. “Letter from John Smeltzer (West Hanover Township, Dauphin County, Pennsylvania) to W. F. Landis, Regarding Farming - April 25, 1869.” Letters (correspondence). Civil War Collection, 1869. Box 9, Folder 29. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/044bnzs8m0-cor.