f:DocumentReference
identifier: maximum cardinality of 'identifier' is 1
subject: minimum cardinality of 'subject' is 1
content: maximum cardinality of 'content' is 1
f:DocumentReference/f:content
format: minimum cardinality of 'format' is 1
format: maximum cardinality of 'format' is 1
f:DocumentReference/f:content/f:attachment
id: maximum cardinality of 'id' is 1
contentType: minimum cardinality of 'contentType' is 1
contentType: maximum cardinality of 'contentType' is 1
language: maximum cardinality of 'language' is 1
data: maximum cardinality of 'data' is 1
url: minimum cardinality of 'url' is 1
url: maximum cardinality of 'url' is 1
size: maximum cardinality of 'size' is 1
hash: maximum cardinality of 'hash' is 1
title: maximum cardinality of 'title' is 1
creation: maximum cardinality of 'creation' is 1