--- a/doc-src/TutorialI/Misc/document/natsum.tex Wed Dec 06 12:34:40 2000 +0100
+++ b/doc-src/TutorialI/Misc/document/natsum.tex Wed Dec 06 13:22:58 2000 +0100
@@ -34,7 +34,7 @@
Isabelle does not prove this completely automatically. Note that \isa{{\isadigit{1}}}
and \isa{{\isadigit{2}}} are available as abbreviations for the corresponding
\isa{Suc}-expressions. If you need the full set of numerals,
-see~\S\ref{nat-numerals}.
+see~\S\ref{sec:numerals}.
\begin{warn}
The constant \ttindexbold{0} and the operations