Fixed index module reference.
diff --git a/Doc/lib/libdbm.tex b/Doc/lib/libdbm.tex
index 977e05c..551a153 100644
--- a/Doc/lib/libdbm.tex
+++ b/Doc/lib/libdbm.tex
@@ -10,7 +10,7 @@
 
 See also the \code{gdbm} module, which provides a similar interface
 using the GNU GDBM library.
-\bimodindex{gdbm}
+\refbimodindex{gdbm}
 
 The module defines the following constant and functions: