add missing "and"

diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex
index 3ba7ca41a2c997fd63e303518d00bb412979d13d..f53d42594c48451e694aea97b9cc20fd1825d4f8 100644 (file)
--- a/Doc/ref/ref3.tex
+++ b/Doc/ref/ref3.tex
@@ -410,8 +410,9 @@ Dictionaries are mutable; they can be created by the
 Displays'').
 
 The extension modules \module{dbm}\refstmodindex{dbm},
-\module{gdbm}\refstmodindex{gdbm}, \module{bsddb}\refstmodindex{bsddb}
-provide additional examples of mapping types.
+\module{gdbm}\refstmodindex{gdbm}, and
+\module{bsddb}\refstmodindex{bsddb} provide additional examples of
+mapping types.
 
 \end{description} % Mapping types