oai-pmh.md

@@ -54,6 +54,7 @@ For the element langstring the attribute xml:lang is used.
 - https://validator.oaipmh.com/
 - https://repository.tugraz.at/
 - https://oer-repo.uibk.ac.at/
+- https://en.wikipedia.org/wiki/Learning_object_metadata
 - https://standards.ieee.org/standard/1484_12_3-2020.html
 - https://oer-repo.uibk.ac.at/lom/latest/
 - https://www.data.gv.at/katalog/dataset/stat_ofos-2012