Occasionally you may encounter a situation where two different sources generate an identical short form footnote.
Chicago style allows for flexibility with shortened subsequent citations to avoid ambiguity and guide the reader to the correct source. The short form footnote should include enough information to remind readers of the full title or lead them to the appropriate entry in the bibliography.
To differentiate between two identical shortened footnotes for different sources, you need to add a distinguishing element to the citation. This could include the name of the journal and volume/issue number for an article (see 14.84 Short titles for articles), and a shortened book title for a chapter in a book.
