If you need to add one or more citations to a paper that has already been formatted, insert the new citations into the text (as described earlier in this chapter) and select Configure Bibliography when you are ready to update the bibliography and citations.
To add a new reference to an existing citation, insert the new reference next to (not within) the existing citation, like this:
(Hockney and Ellis, 1996){Argus, 1984 #1}
Adjacent citations are merged during formatting, and the formatted citations are sorted according to the style:
(Argus, 1984; Hockney and Ellis, 1996)
Note: Do not insert a citation into the middle of a formatted citation. Insert it immediately before or after the existing citation, with no space between them.