Fix typo reported by Michael Soulier.
diff --git a/Doc/ref/refa1.tex b/Doc/ref/refa1.tex
index bd3a38c..28f62ae 100644
--- a/Doc/ref/refa1.tex
+++ b/Doc/ref/refa1.tex
@@ -165,7 +165,7 @@
statement \samp{nested_scopes}. This section begins with a bit of
terminology.
-\subsection{Definitions and rules \label{defintions}}
+\subsection{Definitions and rules \label{definitions}}
\dfn{Names} refer to objects. Names are introduced by name binding
operations. Each occurrence of a name in the program text refers to