To produce a separate bibliography within a chapter, use this package:
\usepackage{chapterbib}
At the point in your document where you want the chapter bibliography to appear, use this command if you are using the author-year citation style:
\begin{chapterbibliography}
…
\end{chapterbibliography}
If you prefer the numbered citation style, append an optional argument like this (assuming you have fewer than 99 references):
\begin{chapterbibliography}[99]
…
\end{chapterbibliography}