diff --git a/htdocs/core/actions_dellink.inc.php b/htdocs/core/actions_dellink.inc.php
index a7ac035506f..60ca4af7409 100644
--- a/htdocs/core/actions_dellink.inc.php
+++ b/htdocs/core/actions_dellink.inc.php
@@ -27,17 +27,42 @@
 // $permissiondellink must be defined
 
 $dellinkid = GETPOST('dellinkid', 'int');
+$addlink = GETPOST('addlink','alpha');
 $addlinkid = GETPOST('idtolinkto', 'int');
+$addlinkref = GETPOST('reftolinkto','alpha');
+$cancellink = GETPOST('cancel','alpha');
 
 // Link invoice to order
-if ($action == 'addlink' && !empty($permissiondellink) && !GETPOST('cancel', 'alpha') && $id > 0 && $addlinkid > 0) {
+if ($action == 'addlink' && !empty($permissiondellink) && !$cancellink && $id > 0 && $addlinkid > 0) {
 	$object->fetch($id);
 	$object->fetch_thirdparty();
-	$result = $object->add_object_linked(GETPOST('addlink', 'alpha'), $addlinkid);
+	$result = $object->add_object_linked($addlink, $addlinkid);
+}
+
+// Link by reference
+if ($action == 'addlinkbyref' && ! empty($permissiondellink) && !$cancellink && $id > 0 && !empty($addlinkref) && !empty($conf->global->MAIN_LINK_BY_REF_IN_LINKTO)) {
+	$element_prop = getElementProperties($addlink);
+	if (is_array($element_prop)) {
+		dol_include_once('/' . $element_prop['classpath'] . '/' . $element_prop['classfile'] . '.class.php');
+
+		$objecttmp = new $element_prop['classname']($db);
+		$ret = $objecttmp->fetch(0, $addlinkref);
+		if ($ret > 0) {
+			$object->fetch($id);
+			$object->fetch_thirdparty();
+			$result = $object->add_object_linked($addlink, $objecttmp->id);
+			if (isset($_POST['reftolinkto'])) unset($_POST['reftolinkto']);
+		} elseif ($ret < 0) {
+			setEventMessages($objecttmp->error, $objecttmp->errors, 'errors');
+		} else {
+			$langs->load('errors');
+			setEventMessage($langs->trans('ErrorRecordNotFound'), 'errors');
+		}
+	}
 }
 
 // Delete link
-if ($action == 'dellink' && !empty($permissiondellink) && !GETPOST('cancel', 'alpha') && $dellinkid > 0) {
+if ($action == 'dellink' && !empty($permissiondellink) && !$cancellink && $dellinkid > 0) {
 	$result = $object->deleteObjectLinked(0, '', 0, '', $dellinkid);
 	if ($result < 0) {
 		setEventMessages($object->error, $object->errors, 'errors');
diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index 9ef0f3ee235..a6280a7c9f5 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -7971,6 +7971,21 @@ class Form
 
 			if (!empty($possiblelink['perms']) && (empty($restrictlinksto) || in_array($key, $restrictlinksto)) && (empty($excludelinksto) || !in_array($key, $excludelinksto))) {
 				print '<div id="'.$key.'list"'.(empty($conf->use_javascript_ajax) ? '' : ' style="display:none"').'>';
+
+				if (!empty($conf->global->MAIN_LINK_BY_REF_IN_LINKTO)) {
+					print '<br><form action="' . $_SERVER["PHP_SELF"] . '" method="POST" name="formlinkedbyref' . $key . '">';
+					print '<input type="hidden" name="id" value="' . $object->id . '">';
+					print '<input type="hidden" name="action" value="addlinkbyref">';
+					print '<input type="hidden" name="addlink" value="' . $key . '">';
+					print '<table class="noborder">';
+					print '<tr>';
+					print '<td>' . $langs->trans("Ref") . '</td>';
+					print '<td><input type="text" name="reftolinkto" value="' . dol_escape_htmltag(GETPOST('reftolinkto', 'alpha')) . '">&nbsp;<input type="submit" class="button valignmiddle" value="' . $langs->trans('ToLink') . '">&nbsp;<input type="submit" class="button" name="cancel" value="' . $langs->trans('Cancel') . '"></td>';
+					print '</tr>';
+					print '</table>';
+					print '</form>';
+				}
+
 				$sql = $possiblelink['sql'];
 
 				$resqllist = $this->db->query($sql);
@@ -8028,7 +8043,7 @@ class Form
 				print '</div>';
 
 				//$linktoelem.=($linktoelem?' &nbsp; ':'');
-				if ($num > 0) {
+				if ($num > 0 || !empty($conf->global->MAIN_LINK_BY_REF_IN_LINKTO)) {
 					$linktoelemlist .= '<li><a href="#linkto'.$key.'" class="linkto dropdowncloseonclick" rel="'.$key.'">'.$langs->trans($possiblelink['label']).' ('.$num.')</a></li>';
 					// } else $linktoelem.=$langs->trans($possiblelink['label']);
 				} else {