diff --git a/include/prestudent.class.php b/include/prestudent.class.php
index ada05c4f9..18ccef232 100644
--- a/include/prestudent.class.php
+++ b/include/prestudent.class.php
@@ -19,6 +19,7 @@
  *          Andreas Oesterreicher <andreas.oesterreicher@technikum-wien.at> and
  *          Rudolf Hangl <rudolf.hangl@technikum-wien.at>.
  */
+require_once(dirname(__FILE__).'/person.class.php');
 
 class prestudent extends person
 {