It is important to take accurate notes when conducting research in unpublished manuscripts and archival material so you can find items again if you need to, and so other researchers will be able to go back to the source when following your footnote or bibliography entry.
Accurately record the collection name, box number, folder number and document details when taking notes. If you are citing correspondence, record the author as well as the recipient, and the date of the letter, if known.
Format your citations as instructed in the finding aid for the collection.
Citing a primary source document, from an archives, varies depending on the preference of your instructor, the publication you are submitting the article, or the discipline in which you are operating. You may wish to consult the Purdue Online Writing Lab (OWL) for further information.
There are several elements to the citation which may be necessary to properly cite a document.
The document: The creator or author, specific item title, page, section, date.
Box and file number: The majority of materials found in archives, that are not books, are housed in some sort of container and within the container the various items are separated for various reasons in files.
Repository: This is the name of the archives.
American Psychological Association:
Tarkington, B. (1924, May 8). [Letter to George Ade]. George Ade Papers, 1878-2007, The Virginia Kelly Karnes Archives and Special Collections Research Center (Box 10, Folder 5), Purdue University Libraries, West Lafayette, IN.