diff --git a/spec/03.04.expressions.tex b/spec/03.04.expressions.tex
index 0d1f95bb5..41df75965 100644
--- a/spec/03.04.expressions.tex
+++ b/spec/03.04.expressions.tex
@@ -37,7 +37,7 @@ property ``$e$ is a reference''. The result of assignment operator coincides wit
 assigns 3 to both "\lstinline|x|" and "\lstinline|y|".
 
 \begin{figure}[h]
-  \newcommand{\Ref}[1]{\mathcal{R}\,({#1})}
+  \renewcommand{\Ref}[1]{\mathcal{R}\,({#1})}
   \renewcommand{\arraystretch}{4}
   \[
     \begin{array}{cc}