\cite
.....
`\cite[text]{key_list}'
The `key_list' argument is a list of citation keys. This command
generates an in-text citation to the references associated with the keys
in `key_list' by entries on the `.aux' file read by the
`\begin{document}' command.
The optional `text' argument will appear after the citation, i.e.
`\cite[p. 2]{knuth}' might produce `[Knuth, p. 2]'.