I crafted a citation for a college yearbook with no difficulty (citing it as a book), but I realized that what I am actually referencing in my writing pertains only to a single copy of that yearbook as I am quoting an autograph written into the yearbook and not the yearbook content itself. This particular yearbook is part of an archive of my in-laws papers and memorabilia. I'm thinking now that this completely changes the citation. I'm thinking now that this should be cited as an artifact from their private collection. Am I on the right path?