diff --git a/src/dsp_tools/resources/schema/data.xsd b/src/dsp_tools/resources/schema/data.xsd
index 99fca9ab88..c6b51352fb 100644
--- a/src/dsp_tools/resources/schema/data.xsd
+++ b/src/dsp_tools/resources/schema/data.xsd
@@ -73,7 +73,7 @@
         <xs:attribute name="encoding" type="encoding_types" use="required"/>
         <xs:attribute name="resrefs" type="resrefs_type"/>
         <xs:attribute name="comment" type="xs:string"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
     </xs:complexType>
 
     <!-- xml encoding value type -->
@@ -84,7 +84,7 @@
         <xs:attribute name="encoding" fixed="xml" use="required"/>
         <xs:attribute name="resrefs" type="resrefs_type"/>
         <xs:attribute name="comment" type="xs:string"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
     </xs:complexType>
 
     <!-- formatted text type -->
@@ -93,7 +93,7 @@
             <xs:any processContents="skip" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:attribute name="comment" type="xs:string"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
     </xs:complexType>
 
     <!-- unformatted text type -->
@@ -101,7 +101,7 @@
         <xs:simpleContent>
             <xs:extension base="nonEmptyString">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -111,7 +111,7 @@
         <xs:simpleContent>
             <xs:extension base="knoracolor_type">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -121,7 +121,7 @@
         <xs:simpleContent>
             <xs:extension base="knoradate_type">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -131,7 +131,7 @@
         <xs:simpleContent>
             <xs:extension base="xs:float">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -141,7 +141,7 @@
         <xs:simpleContent>
             <xs:extension base="xs:string">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -151,7 +151,7 @@
         <xs:simpleContent>
             <xs:extension base="nonEmptyString">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -161,7 +161,7 @@
         <xs:simpleContent>
             <xs:extension base="nonEmptyString">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -171,7 +171,7 @@
         <xs:simpleContent>
             <xs:extension base="xs:integer">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -180,7 +180,7 @@
     <xs:complexType name="hasSegmentBounds_type">
         <xs:sequence />
         <xs:attribute name="comment" type="xs:string"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         <xs:attribute name="segment_start" type="xs:double" use="required"/>
         <xs:attribute name="segment_end" type="xs:double" use="required"/>
     </xs:complexType>
@@ -190,7 +190,7 @@
         <xs:simpleContent>
             <xs:extension base="nonEmptyString">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -200,7 +200,7 @@
         <xs:simpleContent>
             <xs:extension base="nonEmptyString">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -210,7 +210,7 @@
         <xs:simpleContent>
             <xs:extension base="knoratime_type">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -220,7 +220,7 @@
         <xs:simpleContent>
             <xs:extension base="xs:decimal">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -230,7 +230,7 @@
         <xs:simpleContent>
             <xs:extension base="knorauri_type">
                 <xs:attribute name="comment" type="xs:string"/>
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -240,7 +240,7 @@
     <xs:simpleContent>
         <xs:extension base="xs:boolean">
             <xs:attribute name="comment" type="xs:string"/>
-            <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+            <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         </xs:extension>
     </xs:simpleContent>
     </xs:complexType>
@@ -402,7 +402,9 @@
     <xs:complexType name="bitstream_type">
         <xs:simpleContent>
             <xs:extension base="nonEmptyString">
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
+                <xs:attribute name="license" type="xs:IDREF" use="optional"/>
+                <xs:attribute name="copyright-attribution" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -411,7 +413,9 @@
     <xs:complexType name="iiif_uri_type">
         <xs:simpleContent>
             <xs:extension base="nonEmptyString">
-                <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+                <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
+                <xs:attribute name="license" type="xs:IDREF" use="optional"/>
+                <xs:attribute name="copyright-attribution" type="xs:IDREF" use="optional"/>
             </xs:extension>
         </xs:simpleContent>
     </xs:complexType>
@@ -447,7 +451,7 @@
         </xs:attribute>
         <xs:attribute name="restype" type="xs:string" use="required"/>
         <xs:attribute name="id" type="xs:ID" use="required"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         <xs:attribute name="iri" type="xs:string" use="optional"/>
         <xs:attribute name="ark" type="xs:string" use="optional"/>
         <xs:attribute name="creation_date" type="xs:dateTime" use="optional"/>
@@ -461,7 +465,7 @@
         </xs:all>
         <xs:attribute name="label" type="xs:string" use="required"/>
         <xs:attribute name="id" type="xs:ID" use="required"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         <xs:attribute name="iri" type="xs:string" use="optional"/>
         <xs:attribute name="ark" type="xs:string" use="optional"/>
         <xs:attribute name="creation_date" type="xs:dateTime" use="optional"/>
@@ -477,7 +481,7 @@
         </xs:all>
         <xs:attribute name="label" type="xs:string" use="required"/>
         <xs:attribute name="id" type="xs:ID" use="required"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         <xs:attribute name="iri" type="xs:string" use="optional"/>
         <xs:attribute name="ark" type="xs:string" use="optional"/>
         <xs:attribute name="creation_date" type="xs:dateTime" use="optional"/>
@@ -491,7 +495,7 @@
         </xs:all>
         <xs:attribute name="label" type="xs:string" use="required"/>
         <xs:attribute name="id" type="xs:ID" use="required"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         <xs:attribute name="iri" type="xs:string" use="optional"/>
         <xs:attribute name="ark" type="xs:string" use="optional"/>
         <xs:attribute name="creation_date" type="xs:dateTime" use="optional"/>
@@ -510,7 +514,7 @@
         </xs:sequence>
         <xs:attribute name="label" type="xs:string" use="required"/>
         <xs:attribute name="id" type="xs:ID" use="required"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         <xs:attribute name="creation_date" type="xs:dateTime" use="optional"/>
     </xs:complexType>
 
@@ -527,7 +531,7 @@
         </xs:sequence>
         <xs:attribute name="label" type="xs:string" use="required"/>
         <xs:attribute name="id" type="xs:ID" use="required"/>
-        <xs:attribute name="permissions" type="xs:NCName" use="optional"/>
+        <xs:attribute name="permissions" type="xs:IDREF" use="optional"/>
         <xs:attribute name="creation_date" type="xs:dateTime" use="optional"/>
     </xs:complexType>
 
@@ -566,11 +570,46 @@
         <xs:attribute name="id" type="xs:ID" use="required"/>
     </xs:complexType>
 
+    <!-- copyright-attribution tag -->
+    <xs:complexType name="copyright_attribution_type">
+        <xs:simpleContent>
+            <xs:extension base="xs:string">
+                <xs:attribute name="id" type="xs:ID" use="required"/>
+            </xs:extension>
+        </xs:simpleContent>
+    </xs:complexType>
+
+    <!-- copyright-attributions tag -->
+    <xs:complexType name="copyright_attributions_type">
+        <xs:sequence>
+            <xs:element name="copyright-attribution" type="copyright_attribution_type" minOccurs="1" maxOccurs="unbounded"/>
+        </xs:sequence>
+    </xs:complexType>
+
+    <!-- license tag -->
+    <xs:complexType name="license_type">
+        <xs:simpleContent>
+            <xs:extension base="xs:string">
+                <xs:attribute name="id" type="xs:ID" use="required"/>
+                <xs:attribute name="uri" type="xs:string" use="optional"/>
+            </xs:extension>
+        </xs:simpleContent>
+    </xs:complexType>
+
+    <!-- licenses tag -->
+    <xs:complexType name="licenses_type">
+        <xs:sequence>
+            <xs:element name="license" type="license_type" minOccurs="1" maxOccurs="unbounded"/>
+        </xs:sequence>
+    </xs:complexType>
+
     <!-- complete document -->
     <xs:element name="knora">
         <xs:complexType>
             <xs:sequence>
                 <xs:element name="permissions" type="permissions_type" minOccurs="0" maxOccurs="unbounded"/>
+                <xs:element name="copyright-attributions" type="copyright_attributions_type" minOccurs="0" maxOccurs="unbounded"/>
+                <xs:element name="licenses" type="licenses_type" minOccurs="0" maxOccurs="unbounded"/>
                 <xs:choice maxOccurs="unbounded">
                     <xs:element name="resource" type="resource_type" minOccurs="1" maxOccurs="unbounded">
                         <xs:unique name="UniqueNameAttr_Resource">
@@ -619,5 +658,23 @@
             <xs:selector xpath=".//*"/>
             <xs:field xpath="@ark"/>
         </xs:unique>
+        <!-- Define a key constraint for license IDs -->
+        <xs:key name="licenseIdKey">
+            <xs:selector xpath="knora/licenses/license"/>
+            <xs:field xpath="@id"/>
+        </xs:key>
+        <xs:keyref name="licenseIdRef" refer="licenseIdKey">
+            <xs:selector xpath="knora/resource/*"/>
+            <xs:field xpath="@license"/>
+        </xs:keyref>
+        <!-- Define a key constraint for copyright IDs -->
+        <xs:key name="copyright-attributionsIdKey">
+            <xs:selector xpath="knora/copyright-attributions/copyright-attribution"/>
+            <xs:field xpath="@id"/>
+        </xs:key>
+        <xs:keyref name="copyrightIdRef" refer="copyright-attributionsIdKey">
+            <xs:selector xpath="knora/resource/*"/>
+            <xs:field xpath="@copyright-attribution"/>
+        </xs:keyref>
     </xs:element>
 </xs:schema>
diff --git a/test/integration/commands/excel2xml/test_excel2xml_cli.py b/test/integration/commands/excel2xml/test_excel2xml_cli.py
index 643a157ac9..7e587319f6 100644
--- a/test/integration/commands/excel2xml/test_excel2xml_cli.py
+++ b/test/integration/commands/excel2xml/test_excel2xml_cli.py
@@ -98,7 +98,7 @@ def test_missing_resource_permission(self) -> None:
         file = f"{INVALID_EXCEL_DIRECTORY}/missing-resource-permissions.xlsx"
         expected_msg = "Missing permissions for resource 'person_0' (Excel row 2)"
         expected_xml_validation = regex.escape(
-            "Element 'resource', attribute 'permissions': " "'' is not a valid value of the atomic type 'xs:NCName'."
+            "Element 'resource', attribute 'permissions': " "'' is not a valid value of the atomic type 'xs:IDREF'."
         )
         _, catched_warnings = excel2xml_cli.excel2xml(file, "1234", "excel2xml-invalid")
         assert len(catched_warnings) == 2
@@ -124,7 +124,7 @@ def test_missing_bitstream_permission(self) -> None:
             " An attempt to deduce them from the resource permissions failed."
         )
         expected_xml_validation = regex.escape(
-            "Element 'bitstream', attribute 'permissions': " "'' is not a valid value of the atomic type 'xs:NCName'."
+            "Element 'bitstream', attribute 'permissions': " "'' is not a valid value of the atomic type 'xs:IDREF'."
         )
         _, catched_warnings = excel2xml_cli.excel2xml(file, "1234", "excel2xml-invalid")
         assert len(catched_warnings) == 3
diff --git a/test/integration/utils/test_xml_validation.py b/test/integration/utils/test_xml_validation.py
index 4c23ce40ff..c59705a61d 100644
--- a/test/integration/utils/test_xml_validation.py
+++ b/test/integration/utils/test_xml_validation.py
@@ -68,5 +68,16 @@ def test_validate_xml_empty_label() -> None:
         validate_xml_file(input_file="testdata/invalid-testdata/xml-data/empty-label.xml")
 
 
+def test_validate_xml_duplicate_license_copyright_id() -> None:
+    expected_msg = regex.escape(
+        "The XML file cannot be uploaded due to the following validation error(s):\n"
+        "    Line 11: Element 'copyright-attribution', attribute 'id': 'copyright_id' "
+        "is not a valid value of the atomic type 'xs:ID'.\n"
+        "    Line 16: Element 'license', attribute 'id': 'license_id' is not a valid value of the atomic type 'xs:ID'."
+    )
+    with pytest.raises(InputError, match=expected_msg):
+        validate_xml_file(input_file="testdata/invalid-testdata/xml-data/duplicate-license-copyright-ids.xml")
+
+
 if __name__ == "__main__":
     pytest.main([__file__])
diff --git a/testdata/invalid-testdata/xml-data/duplicate-license-copyright-ids.xml b/testdata/invalid-testdata/xml-data/duplicate-license-copyright-ids.xml
new file mode 100644
index 0000000000..4a3265ec15
--- /dev/null
+++ b/testdata/invalid-testdata/xml-data/duplicate-license-copyright-ids.xml
@@ -0,0 +1,19 @@
+<?xml version='1.0' encoding='utf-8'?>
+
+<knora xmlns="https://dasch.swiss/schema"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xsi:schemaLocation="https://dasch.swiss/schema ../../../src/dsp_tools/resources/schema/data.xsd"
+       shortcode="4124"
+       default-ontology="testonto">
+
+    <copyright-attributions>
+        <copyright-attribution id="copyright_id">Copyright Text</copyright-attribution>
+        <copyright-attribution id="copyright_id">Copyright Text</copyright-attribution>
+    </copyright-attributions>
+
+    <licenses>
+        <license id="license_id">license text</license>
+        <license id="license_id">license text</license>
+    </licenses>
+
+</knora>
diff --git a/testdata/xml-data/test-data-systematic.xml b/testdata/xml-data/test-data-systematic.xml
index 5c5cd46820..7fe4523e20 100644
--- a/testdata/xml-data/test-data-systematic.xml
+++ b/testdata/xml-data/test-data-systematic.xml
@@ -29,6 +29,37 @@
         <allow group="systematic-tp:testgroupEditors">M</allow>
     </permissions>
 
+    <copyright-attributions>
+        <copyright-attribution id="copyright_id">Copyright Text</copyright-attribution>
+    </copyright-attributions>
+
+    <licenses>
+        <license id="CC-BY" uri="https://creativecommons.org/licenses/by/4.0/">
+            CC BY 4.0
+        </license>
+        <license id="CC-BY-SA" uri="https://creativecommons.org/licenses/by-sa/4.0/">
+            CC BY-SA 4.0
+        </license>
+        <license id="CC-BY-NC" uri="https://creativecommons.org/licenses/by-nc/4.0/">
+            CC BY-NC 4.0
+        </license>
+        <license id="CC-BY-NC-SA" uri="https://creativecommons.org/licenses/by-nc-sa/4.0/">
+            CC BY-NC-SA 4.0
+        </license>
+        <license id="CC-BY-ND" uri="https://creativecommons.org/licenses/by-nd/4.0/">
+            CC BY-ND 4.0
+        </license>
+        <license id="CC-BY-NC-ND" uri="https://creativecommons.org/licenses/by-nc-nd/4.0/">
+            CC BY-NC-ND 4.0
+        </license>
+        <license id="CC0" uri="https://creativecommons.org/publicdomain/zero/1.0/">
+            CC0 1.0
+        </license>
+         <license id="twoLineLicense">
+            First Line.
+            Second Line.
+        </license>
+    </licenses>
 
     <resource label="TestthingWithArk1"
               restype=":TestThing2"
@@ -281,6 +312,22 @@
         </text-prop>
     </resource>
 
+    <resource label="iiif-link with license / copyright"
+              restype=":ImageThing"
+              id="iiif-link-license-copyright"
+              permissions="open">
+        <iiif-uri
+                license="twoLineLicense"
+                copyright-attribution="copyright_id"
+        >https://iiif.wellcomecollection.org/image/b20432033_B0008608.JP2/full/1338%2C/0/default.jpg</iiif-uri>
+        <text-prop name=":hasSimpleText">
+            <text permissions="open" encoding="utf8">
+                Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0).
+                Credit: Zebrafish embryo. Source: Wellcome Collection.
+            </text>
+        </text-prop>
+    </resource>
+
     <resource label="iiif-link"
               restype=":ImageThing"
               id="iiif-link"
@@ -298,7 +345,10 @@
               restype=":ImageThing"
               id="image_thing_1"
               permissions="open">
-        <bitstream>testdata/bitstreams/test.tiff</bitstream>
+        <bitstream
+                license="CC-BY-NC"
+                copyright-attribution="copyright_id"
+        >testdata/bitstreams/test.tiff</bitstream>
         <text-prop name=":hasSimpleText">
             <text permissions="open" encoding="utf8">This is a Imagething as TIFF</text>
         </text-prop>