diff --git a/htdocs/core/lib/pdf.lib.php b/htdocs/core/lib/pdf.lib.php
index ca94353ee19..709d6e5d404 100644
--- a/htdocs/core/lib/pdf.lib.php
+++ b/htdocs/core/lib/pdf.lib.php
@@ -2359,13 +2359,13 @@ function pdf_getLinkedObjects(&$object, $outputlangs)
 			if (count($objects) > 1 && count($objects) <= (getDolGlobalInt("MAXREFONDOC") ? getDolGlobalInt("MAXREFONDOC") : 10)) {
 				$object->note_public = dol_concatdesc($object->note_public, '<br>'.$outputlangs->transnoentities("RefOrder").' : <br>');
 				foreach ($objects as $elementobject) {
-					$object->note_public = dol_concatdesc($object->note_public, $outputlangs->transnoentities($elementobject->ref).($elementobject->ref_client ? ' ('.$elementobject->ref_client.')' : '').($elementobject->ref_supplier ? ' ('.$elementobject->ref_supplier.')' : '').' ');
+					$object->note_public = dol_concatdesc($object->note_public, $outputlangs->transnoentities($elementobject->ref).(!empty($elementobject->ref_client) ? ' ('.$elementobject->ref_client.')' : '').(!empty($elementobject->ref_supplier) ? ' ('.$elementobject->ref_supplier.')' : '').' ');
 					$object->note_public = dol_concatdesc($object->note_public, $outputlangs->transnoentities("OrderDate").' : '.dol_print_date($elementobject->date, 'day', '', $outputlangs).'<br>');
 				}
 			} elseif (count($objects) == 1) {
 				$elementobject = array_shift($objects);
 				$linkedobjects[$objecttype]['ref_title'] = $outputlangs->transnoentities("RefOrder");
-				$linkedobjects[$objecttype]['ref_value'] = $outputlangs->transnoentities($elementobject->ref).($elementobject->ref_client ? ' ('.$elementobject->ref_client.')' : '').($elementobject->ref_supplier ? ' ('.$elementobject->ref_supplier.')' : '');
+				$linkedobjects[$objecttype]['ref_value'] = $outputlangs->transnoentities($elementobject->ref).(!empty($elementobject->ref_client) ? ' ('.$elementobject->ref_client.')' : '').(!empty($elementobject->ref_supplier) ? ' ('.$elementobject->ref_supplier.')' : '');
 				$linkedobjects[$objecttype]['date_title'] = $outputlangs->transnoentities("OrderDate");
 				$linkedobjects[$objecttype]['date_value'] = dol_print_date($elementobject->date, 'day', '', $outputlangs);
 			}