diff --git a/plugins/libkolab/lib/kolab_format.php b/plugins/libkolab/lib/kolab_format.php
index 1fe8e611..0f19e1a9 100644
--- a/plugins/libkolab/lib/kolab_format.php
+++ b/plugins/libkolab/lib/kolab_format.php
@@ -3,6 +3,9 @@
 /**
  * Kolab format model class wrapping libkolabxml bindings
  *
+ * Abstract base class for different Kolab groupware objects read from/written
+ * to the new Kolab 3 format using the PHP bindings of libkolabxml.
+ *
  * @version @package_version@
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
diff --git a/plugins/libkolab/lib/kolab_format_contact.php b/plugins/libkolab/lib/kolab_format_contact.php
index 9d56b83b..daef994f 100644
--- a/plugins/libkolab/lib/kolab_format_contact.php
+++ b/plugins/libkolab/lib/kolab_format_contact.php
@@ -1,5 +1,26 @@
 <?php
 
+/**
+ * Kolab Contact model class
+ *
+ * @version @package_version@
+ * @author Thomas Bruederli <bruederli@kolabsys.com>
+ *
+ * Copyright (C) 2012, Kolab Systems AG <contact@kolabsys.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
 
 class kolab_format_contact extends kolab_format
 {
diff --git a/plugins/libkolab/lib/kolab_format_distributionlist.php b/plugins/libkolab/lib/kolab_format_distributionlist.php
index b064718c..84771765 100644
--- a/plugins/libkolab/lib/kolab_format_distributionlist.php
+++ b/plugins/libkolab/lib/kolab_format_distributionlist.php
@@ -1,5 +1,26 @@
 <?php
 
+/**
+ * Kolab Distribution List model class
+ *
+ * @version @package_version@
+ * @author Thomas Bruederli <bruederli@kolabsys.com>
+ *
+ * Copyright (C) 2012, Kolab Systems AG <contact@kolabsys.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
 
 class kolab_format_distributionlist extends kolab_format
 {
diff --git a/plugins/libkolab/lib/kolab_format_event.php b/plugins/libkolab/lib/kolab_format_event.php
index 00035e93..6a262aff 100644
--- a/plugins/libkolab/lib/kolab_format_event.php
+++ b/plugins/libkolab/lib/kolab_format_event.php
@@ -1,5 +1,26 @@
 <?php
 
+/**
+ * Kolab Event model class
+ *
+ * @version @package_version@
+ * @author Thomas Bruederli <bruederli@kolabsys.com>
+ *
+ * Copyright (C) 2012, Kolab Systems AG <contact@kolabsys.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
 
 class kolab_format_event extends kolab_format
 {