oai-pmh.md

@@ -56,6 +56,7 @@ For the element langstring the attribute xml:lang is used.
   <lom:langstring xml:lang="x-none">Author</lom:langstring>
 </lom:value>
 ```
+> The repository has to ensure that the language code corresponds to the text!
 
 ## Links
 - https://www.openarchives.org/