diff --git a/Doc/lib/libftplib.tex b/Doc/lib/libftplib.tex
index 105ccdf..acd8784 100644
--- a/Doc/lib/libftplib.tex
+++ b/Doc/lib/libftplib.tex
@@ -1,3 +1,6 @@
 \section{Built-in module \sectcode{ftplib}}
 \stmodindex{ftplib}
+
+\renewcommand{\indexsubitem}{(in module ftplib)}
+
 To be provided.