Citations to primary sources held in Special Collections & Archives should indicate clearly the source of the material used so that future researchers can locate these materials readily.
The Archives of Ontario has issued a Guide to Citing Archival Records (PDF) that may be helpful.
The examples on this page are based on The Chicago Manual of Style and illustrate the elements that are important in documenting unpublished material. The library has many style manuals that will help you with proper format of citations.
The first reference should include the complete information necessary to identify the document and its location.
A citation to a letter should include the names of the sender and the recipient, followed by the date of the letter and the collection to which it belongs. It is not necessary to use the word “letter.”
Elizabeth Smith Shortt, diary entry, 5 May 1912, Elizabeth Smith Shortt Collection, University of Waterloo Library.
Subsequent references to the same collection may be abbreviated: