SF bug 1415455, fix typo in module name
diff --git a/Doc/lib/libsubprocess.tex b/Doc/lib/libsubprocess.tex
index d077e82..f48b29b 100644
--- a/Doc/lib/libsubprocess.tex
+++ b/Doc/lib/libsubprocess.tex
@@ -387,7 +387,7 @@
 (child_stdout, child_stdin) = (p.stdout, p.stdin)
 \end{verbatim}
 
-The popen2.Popen3 and popen3.Popen4 basically works as subprocess.Popen,
+The popen2.Popen3 and popen2.Popen4 basically works as subprocess.Popen,
 except that:
 
 \begin{itemize}