Archival material includes both manuscript and unpublished material in paper, video, image, etc. formats. This material can be one of the most intimidating resources to cite but all necessary information should be able to be found in the HOLLIS record, in the finding aid, if available, or written on the box and/or folder.
The Schlesinger Library has its own format for citing items from their collection, as do many other repositories, but if none is required by the repository, archival material can be cited using whichever style guide is used for other resources in the your research. The format for the Schlesinger Library is:
Collection name. Item description, dates. Call#, Item/Folder#. Schlesinger Library, Radcliffe Institute, Harvard University, Cambridge, Mass. Finding aid/HOLLIS catalog record url. Date accessed.
Example citation:
Papers of Julia Child, 1925-1993. Journal, 1974. MC 644, item 4. Schlesinger Library, Radcliffe Institute, Cambridge, Mass. https://id.lib.harvard.edu/ead/c/sch00222c00006/catalog. Accessed April 09, 2020.
MLA:
Child, Julia. Journal, 1974. 1974. Papers of Julia Child, 1925-1993. Schlesinger Library on the History of Women in America, Radcliffe Institute, https://id.lib.harvard.edu/ead/c/sch00222c00006/catalog.
APA:
Child, J. (1974). Journal, 1974. [Unpublished journal]. Papers of Julia Child, 1925-1993(MC 644, item 4). Schlesinger Library on the History of Women in America, Radcliffe Institute, https://id.lib.harvard.edu/ead/c/sch00222c00006/catalog.
Chicago Notes:
Child, Julia. Journal, 1974. 1974. MC 644, item 4. Papers of Julia Child, 1925-1993. Schlesinger Library on the History of Women in America, Radcliffe Institute, Cambridge, Mass. https://id.lib.harvard.edu/ead/c/sch00222c00006/catalog.
Chicago Author-Date:
Child, Julia. 1974. Journal, 1974. MC 644, item 4. Papers of Julia Child, 1925-1993. Schlesinger Library on the History of Women in America, Radcliffe Institute, Cambridge, Mass. https://id.lib.harvard.edu/ead/c/sch00222c00006/catalog.
The following information is all that you need to produce a complete citation and can be found in the HOLLIS record, in the finding aid, if available, or written on the box and/or folder. For an example, see the HOLLIS record and finding aid for the Papers of Julia Child.