oai-pmh.md

@@ -44,6 +44,8 @@ As mentioned above, some implementaion are returning content-type as _text/xml_
 ## Optional Elements
 - **Thumbnail** - t.b.d
 
+## Custom LOM Elements
+### centity
 _centity_ is a customized element, which is introduced by edu-sharing for vcard support (used by UIBK). _entity_ is the default one (used by TUGraz).
 For the element langstring the attribute xml:lang is used. 
 ```