diff -r 4015fdd0bcf0 -r d1bacec57f5e doc-src/TutorialI/Sets/sets.tex
--- a/doc-src/TutorialI/Sets/sets.tex	Fri Nov 03 10:26:23 2000 +0100
+++ b/doc-src/TutorialI/Sets/sets.tex	Fri Nov 03 16:53:39 2000 +0100
@@ -633,6 +633,7 @@
 
 
 \section{Relations}
+\label{sec:Relations}
 
 A \textbf{relation} is a set of pairs.  As such, the set operations apply
 to them.  For instance, we may form the union of two relations.  Other