diff --git a/Models/CalendarMapper.php b/Models/CalendarMapper.php
index 5cae0da..9048c1d 100644
--- a/Models/CalendarMapper.php
+++ b/Models/CalendarMapper.php
@@ -56,8 +56,8 @@ class CalendarMapper extends DataMapperAbstract
      */
     protected static $hasMany = [
         'events' => [
-            'mapper'         => '\Modules\Calendar\Models\EventMapper',
-            'relationmapper' => '\Modules\Calendar\Models\EventMapper',
+            'mapper'         => \Modules\Calendar\Models\EventMapper::class
+            'relationmapper' => \Modules\Calendar\Models\EventMapper::class
             'table'          => 'calendar_event',
             'dst'            => 'calendar_event_calendar',
             'src'            => null,
diff --git a/Models/EventMapper.php b/Models/EventMapper.php
index d8084e0..9dbc9c3 100644
--- a/Models/EventMapper.php
+++ b/Models/EventMapper.php
@@ -60,7 +60,7 @@ class EventMapper extends DataMapperAbstract
      */
     protected static $hasOne = [
         'schedule' => [
-            'mapper' => '\Modules\Calendar\Models\ScheduleMapper',
+            'mapper' => \Modules\Calendar\Models\ScheduleMapper::class,
             'src'    => 'calendar_event_schedule',
         ],
     ];