diff --git a/Doc/libmath.tex b/Doc/libmath.tex
index 765fcdf..935b940 100644
--- a/Doc/libmath.tex
+++ b/Doc/libmath.tex
@@ -1,4 +1,5 @@
 \section{Built-in Module \sectcode{math}}
+\label{module-math}
 
 \bimodindex{math}
 \renewcommand{\indexsubitem}{(in module math)}
@@ -70,3 +71,7 @@
 \else
 \code{pi} and \code{e}.
 \fi
+
+\begin{seealso}
+\seealso{cmath}{versions of these functions that can handle complex numbers}
+\end{seealso}