MLA
Willard, Levi. Excerpts from Grandfather's Letters to His Children, Written by Levi Willard, Providing Excerpts of Letters Written by Levi Willard's Grandfather. Includes a Contextual Note by J. J. Willard, Levi Willard's Grandson. 1868. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 9, Folder 47. https://digital.library.emory.edu/purl/648ffbg8cp-cor.
APA, 6th edition
Willard, L. (1868). Excerpts from Grandfather's Letters to his Children, written by Levi Willard, providing excerpts of letters written by Levi Willard's grandfather. Includes a contextual note by J. J. Willard, Levi Willard's grandson (Box 9, Folder 47) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/648ffbg8cp-cor.
Chicago
Willard, Levi. “Excerpts from Grandfather's Letters to His Children, Written by Levi Willard, Providing Excerpts of Letters Written by Levi Willard's Grandfather. Includes a Contextual Note by J. J. Willard, Levi Willard's Grandson.” Letters (correspondence). Civil War Collection, 1868. Box 9, Folder 47. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/648ffbg8cp-cor.