diff --git a/date/date_handler_field_multiple.inc b/date/date_handler_field_multiple.inc
index 7cec65b..6906f85 100644
--- a/date/date_handler_field_multiple.inc
+++ b/date/date_handler_field_multiple.inc
@@ -54,7 +54,7 @@ class date_handler_field_multiple extends content_handler_field_multiple {
     );
   }
 
-  function pre_render(&$values) {
+  function pre_render($values) {
 
     // If there are no values to render (displaying a summary, or query returned no results),
     // or if this is not a grouped field, do nothing specific.