Subscribe to The Chicago Manual of Style Online
Citation, Documentation of Sources
Q. When citing multiple sources in one sentence, would you create multiple footnotes separated by commas at the end of the sentence? Or is there a way to combine sources in one footnote?
A. Some styles allow for more than one note reference at a time, like this.1,2 But in Chicago style, you should use only one note reference at a time, like this.1 When a single note needs to cite multiple sources, the sources are usually separated in the note by semicolons. For more information, including examples, see CMOS 14.28 and 14.57.