\begin{thebibliography}{1}

\bibitem{LL:1977}
L.~D. Landau and E.~M. Lifshitz.
\newblock {\em Quantum Mechanics: Non-relativistic theory}, volume~3 of {\em
  Course of Theoretical Physics}.
\newblock Pergamon Press, Oxford; New York, third edition, 1989, c1977.

\bibitem{Peccei:1989}
R.~D. Peccei.
\newblock Special topics: The strong {CP} problem.
\newblock In C.~Jarlskog, editor, {\em CP violation}. World Scientific,
  Singapore, January 1989.

\bibitem{Turner:1999}
M.~S. Turner.
\newblock Dark matter, dark energy and fundamental physics.
\newblock astro-ph/9912211, December 1999.

\bibitem{Wandelt:2000ad}
Benjamin~D. Wandelt, Romeel Dave, Glennys~R. Farrar, Patrick~C. McGuire,
  David~N. Spergel, and Paul~J. Steinhardt.
\newblock Self-interacting dark matter.
\newblock 2000.

\end{thebibliography}