diff --git a/htdocs/accountancy/bookkeeping/thirdparty_lettering_supplier.php b/htdocs/accountancy/bookkeeping/thirdparty_lettering_supplier.php
index 3795099c78d..fab30066982 100644
--- a/htdocs/accountancy/bookkeeping/thirdparty_lettering_supplier.php
+++ b/htdocs/accountancy/bookkeeping/thirdparty_lettering_supplier.php
@@ -197,7 +197,7 @@ if ($resql) {
 	print '<form name="add" action="'.$_SERVER["PHP_SELF"].'?socid=' . $object->id . '" method="POST">';
 	print '<input type="hidden" name="socid" value="' . $object->id . '">';
 
-    $letteringbutton = '<a class="divButAction"><span class="valignmiddle"><input class="butAction" type="submit" value="lettering" name="lettering" id="lettering"></span></a>\';
+    $letteringbutton = '<a class="divButAction"><span class="valignmiddle"><input class="butAction" type="submit" value="lettering" name="lettering" id="lettering"></span></a>';
 
     print_barre_liste($title, $page, $_SERVER["PHP_SELF"], $param, $sortfield, $sortorder, '', $num, $nbtotalofrecords, 'title_companies', 0, $letteringbutton, '', $limit);