diff -Naur biblio_old/biblio.module biblio/biblio.module
--- biblio_old/biblio.module	2013-12-09 22:53:19.000000000 -0300
+++ biblio/biblio.module	2014-09-26 21:46:26.000000000 -0300
@@ -2377,7 +2377,7 @@
  * @param $new_node
  * @return unknown_type
  */
-function biblio_diff(&$old_node, &$new_node) {
+function biblio_diff($old_node, $new_node) {
   module_load_include('inc', 'biblio', 'includes/biblio.contributors');
 
   $result = array();
@@ -2417,8 +2417,8 @@
     }
     $result[$name] = array(
       '#name' => $field->title,
-      '#old' => explode("\n", $old),
-      '#new' => explode("\n", $new),
+      '#old' => is_array($old)? array_values($old) : explode("\n", $old),
+      '#new' => is_array($new)? array_values($new) : explode("\n", $new),
     );
   }
   return $result;