\newblock W3C Recommendation 21 February 2001,
\url{http://www.w3.org/TR/MathML2}.
+\bibitem{paramodulation}
+Nieuwenhuis, R. and A. Rubio: 2001, `Paramodulation-based thorem proving'.
+\newblock In: J.~A. Robinson and A. Voronkov (eds.): {\em Handbook of Automated
+ Reasoning}. pp. 471--443.
+
\bibitem{omdoc}
OMDoc: 2005, `{OMDoc}: An Open Markup Format for Mathematical Documents
(Version 1.1)'.