diff --git a/share/sgml/man-refs.ent b/share/sgml/man-refs.ent
index 235e5a0d12..2c8e40d36b 100644
--- a/share/sgml/man-refs.ent
+++ b/share/sgml/man-refs.ent
@@ -2991,6 +2991,7 @@
 <!ENTITY man.fxp.4 "<citerefentry/<refentrytitle/fxp/<manvolnum/4//">
 <!ENTITY man.geom.4 "<citerefentry/<refentrytitle/geom/<manvolnum/4//">
 <!ENTITY man.gif.4 "<citerefentry/<refentrytitle/gif/<manvolnum/4//">
+<!ENTITY man.gre.4 "<citerefentry/<refentrytitle/gre/<manvolnum/4//">
 <!ENTITY man.gsc.4 "<citerefentry/<refentrytitle/gsc/<manvolnum/4//">
 <!ENTITY man.gusc.4 "<citerefentry/<refentrytitle/gusc/<manvolnum/4//">
 <!ENTITY man.gx.4 "<citerefentry/<refentrytitle/gx/<manvolnum/4//">