\documentclass{article}
\usepackage{bibtopic}
\begin{document}
There should be an alpha bibliography here
\bibliographystyle{alpha}
\begin{btSect}{biblioa}
  \btPrintAll
\end{btSect}
and a plain one here
\bibliographystyle{plain}
\begin{btSect}{bibliob}
  \btPrintAll
\end{btSect}
\end{document}
