oai-pmh.md

@@ -33,12 +33,16 @@ As mentioned above, some implementaion are returning content-type as _text/xml_
 
 ## Required Elements
 - **Title** - lom.general.title
-- **Descripton** - lom.general.description
 - **Author** - lom.lifecycle.contribute.role.value (=Author) and the Name in lom.lifecycle.contribute.centity.vcard or lom.lifecycle.contribue.entity.langstring
 - **Mediatyp** - lom.technical.format (mime/types)
-- **License** - lom.rights.description (CC-BY)
+- **License** - lom.rights.description (not only CC-BY, new: spdx.org/licenses)
 - **Classification** - lom.classification.taxonpath (Öfos)
+- **Educational** - lom.educational.learningresourcetype
 - **last changed Date/Upload** - lom.lifecycle.version.datetime (custom element)
+## Preferred optional Elements
+- **Descripton** - lom.general.description
+## Optional Elements
+- **Thumbnail** - t.b.d
 
 _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.