diff --git a/Doc/lib/libsys.tex b/Doc/lib/libsys.tex
index 38bd282..76aaefd 100644
--- a/Doc/lib/libsys.tex
+++ b/Doc/lib/libsys.tex
@@ -482,3 +482,9 @@
   Python.
   Availability: Windows.
 \end{datadesc}
+
+
+\begin{seealso}
+  \seemodule{site}
+    {This describes how to use .pth files to extend \code{sys.path}.}
+\end{seealso}