# Sort bibliography automatically

I did not take care of the alphabetical order when I was adding references to the bibliography. So I have a big list with references not ordered. Is there a way to do it automatically? I use

\bibliographystyle{plain}
\def\cprime{$'$}
\begin{thebibliography}{10}

\bibitem{aza}
A. Nash
\newblock{\em Nice book }
\newblock{ Springer}

\end{thebibliography}


3. You can use the string functions of expl3. But you also have to program.