diff --git a/lib/metanorma/ribose/basicdoc.rng b/lib/metanorma/ribose/basicdoc.rng
index 83a23e6..d00d380 100644
--- a/lib/metanorma/ribose/basicdoc.rng
+++ b/lib/metanorma/ribose/basicdoc.rng
@@ -1,10 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <grammar xmlns="http://relaxng.org/ns/structure/1.0" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
-  <include href="biblio.rng">
-    <start>
-      <ref name="document"/>
-    </start>
-  </include>
   <define name="document">
     <element name="document">
       <optional>
@@ -1125,26 +1120,4 @@
       </zeroOrMore>
     </element>
   </define>
-  <define name="ext">
-    <element name="ext">
-      <ref name="BibDataExtensionType"/>
-    </element>
-  </define>
-  <define name="BibDataExtensionType">
-    <ref name="doctype"/>
-  </define>
-  <define name="doctype">
-    <element name="doctype">
-      <ref name="DocumentType"/>
-    </element>
-  </define>
-  <define name="DocumentType">
-    <value>document</value>
-  </define>
-  <define name="BibData">
-    <ref name="BibliographicItem"/>
-    <optional>
-      <ref name="ext"/>
-    </optional>
-  </define>
 </grammar>
diff --git a/lib/metanorma/ribose/biblio-standoc.rng b/lib/metanorma/ribose/biblio-standoc.rng
new file mode 100644
index 0000000..93fe488
--- /dev/null
+++ b/lib/metanorma/ribose/biblio-standoc.rng
@@ -0,0 +1,164 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<grammar xmlns="http://relaxng.org/ns/structure/1.0">
+  <!--
+    Add-ons to biblio.rnc for standoc model: defines the extension point BibDataExtensionType
+    of relaton
+    
+    Specialisations as for biblio.rnc. Extension point can be redefined completely for a flavour of standoc
+    (SDO); but other elements in Bibdata can only be extended (more specialised vocabularies for Bibdata)
+  -->
+  <include href="biblio.rng">
+    <define name="BibData">
+      <ref name="BibliographicItem"/>
+      <optional>
+        <ref name="ext"/>
+      </optional>
+    </define>
+  </include>
+  <define name="ext">
+    <element name="ext">
+      <ref name="BibDataExtensionType"/>
+    </element>
+  </define>
+  <define name="BibDataExtensionType">
+    <optional>
+      <attribute name="schema-version"/>
+    </optional>
+    <ref name="doctype"/>
+    <optional>
+      <ref name="docsubtype"/>
+    </optional>
+    <optional>
+      <ref name="editorialgroup"/>
+    </optional>
+    <zeroOrMore>
+      <ref name="ics"/>
+    </zeroOrMore>
+    <zeroOrMore>
+      <ref name="structuredidentifier"/>
+    </zeroOrMore>
+  </define>
+  <define name="doctype">
+    <element name="doctype">
+      <optional>
+        <attribute name="abbreviation"/>
+      </optional>
+      <ref name="DocumentType"/>
+    </element>
+  </define>
+  <define name="DocumentType">
+    <value>document</value>
+  </define>
+  <define name="docsubtype">
+    <element name="subdoctype">
+      <ref name="DocumentSubtype"/>
+    </element>
+  </define>
+  <define name="DocumentSubtype">
+    <text/>
+  </define>
+  <define name="editorialgroup">
+    <element name="editorialgroup">
+      <oneOrMore>
+        <ref name="technical-committee"/>
+      </oneOrMore>
+    </element>
+  </define>
+  <define name="technical-committee">
+    <element name="technical-committee">
+      <ref name="IsoWorkgroup"/>
+    </element>
+  </define>
+  <define name="IsoWorkgroup">
+    <optional>
+      <attribute name="number"/>
+    </optional>
+    <optional>
+      <attribute name="type"/>
+    </optional>
+    <optional>
+      <attribute name="identifier"/>
+    </optional>
+    <optional>
+      <attribute name="prefix"/>
+    </optional>
+    <text/>
+  </define>
+  <define name="ics">
+    <element name="ics">
+      <element name="code">
+        <text/>
+      </element>
+      <optional>
+        <element name="text">
+          <text/>
+        </element>
+      </optional>
+    </element>
+  </define>
+  <define name="structuredidentifier">
+    <element name="structuredidentifier">
+      <optional>
+        <attribute name="type"/>
+      </optional>
+      <oneOrMore>
+        <element name="agency">
+          <text/>
+        </element>
+      </oneOrMore>
+      <optional>
+        <element name="class">
+          <text/>
+        </element>
+      </optional>
+      <element name="docnumber">
+        <text/>
+      </element>
+      <optional>
+        <element name="partnumber">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="edition">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="version">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="supplementtype">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="supplementnumber">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="amendment">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="corrigendum">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="language">
+          <text/>
+        </element>
+      </optional>
+      <optional>
+        <element name="year">
+          <text/>
+        </element>
+      </optional>
+    </element>
+  </define>
+</grammar>
diff --git a/lib/metanorma/ribose/biblio.rng b/lib/metanorma/ribose/biblio.rng
index 6511f02..d7a9bbf 100644
--- a/lib/metanorma/ribose/biblio.rng
+++ b/lib/metanorma/ribose/biblio.rng
@@ -33,9 +33,10 @@
       <param name="pattern">([\+\-]?\d{4})((-?)((0[1-9]|1[0-2])((-?)([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6]))))?</param>
     </data>
   </define>
-  <start>
-    <ref name="bibitem"/>
-  </start>
+  <!-- start = bibitem -->
+  <define name="BibData">
+    <ref name="BibliographicItem"/>
+  </define>
   <define name="status">
     <element name="status">
       <ref name="stage"/>
@@ -170,27 +171,25 @@
   </define>
   <define name="contributor">
     <element name="contributor">
-      <zeroOrMore>
+      <oneOrMore>
         <ref name="role"/>
-      </zeroOrMore>
+      </oneOrMore>
       <ref name="ContributorInfo"/>
     </element>
   </define>
   <define name="role">
     <element name="role">
-      <optional>
-        <attribute name="type">
-          <choice>
-            <value>author</value>
-            <value>performer</value>
-            <value>publisher</value>
-            <value>editor</value>
-            <value>adapter</value>
-            <value>translator</value>
-            <value>distributor</value>
-          </choice>
-        </attribute>
-      </optional>
+      <attribute name="type">
+        <choice>
+          <value>author</value>
+          <value>performer</value>
+          <value>publisher</value>
+          <value>editor</value>
+          <value>adapter</value>
+          <value>translator</value>
+          <value>distributor</value>
+        </choice>
+      </attribute>
       <zeroOrMore>
         <ref name="roledescription"/>
       </zeroOrMore>
@@ -512,6 +511,17 @@
   </define>
   <define name="localityStack">
     <element name="localityStack">
+      <optional>
+        <attribute name="connective">
+          <choice>
+            <value>and</value>
+            <value>or</value>
+            <value>from</value>
+            <value>to</value>
+            <value/>
+          </choice>
+        </attribute>
+      </optional>
       <zeroOrMore>
         <ref name="locality"/>
       </zeroOrMore>
@@ -524,6 +534,17 @@
   </define>
   <define name="sourceLocalityStack">
     <element name="sourceLocalityStack">
+      <optional>
+        <attribute name="connective">
+          <choice>
+            <value>and</value>
+            <value>or</value>
+            <value>from</value>
+            <value>to</value>
+            <value/>
+          </choice>
+        </attribute>
+      </optional>
       <zeroOrMore>
         <ref name="sourceLocality"/>
       </zeroOrMore>
@@ -626,6 +647,9 @@
         <ref name="BibItemType"/>
       </attribute>
     </optional>
+    <optional>
+      <attribute name="schema-version"/>
+    </optional>
     <optional>
       <ref name="fetched"/>
     </optional>
@@ -720,6 +744,9 @@
         <ref name="BibItemType"/>
       </attribute>
     </optional>
+    <optional>
+      <attribute name="schema-version"/>
+    </optional>
     <optional>
       <ref name="fetched"/>
     </optional>
diff --git a/lib/metanorma/ribose/isodoc.rng b/lib/metanorma/ribose/isodoc.rng
index f85a728..c39d898 100644
--- a/lib/metanorma/ribose/isodoc.rng
+++ b/lib/metanorma/ribose/isodoc.rng
@@ -19,19 +19,7 @@
 -->
 <grammar xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0" xmlns="http://relaxng.org/ns/structure/1.0" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
   <include href="reqt.rng"/>
-  <!-- include "biblio.rnc" { } -->
   <include href="basicdoc.rng">
-    <start>
-      <ref name="standard-document"/>
-    </start>
-    <define name="doctype">
-      <element name="doctype">
-        <optional>
-          <attribute name="abbreviation"/>
-        </optional>
-        <ref name="DocumentType"/>
-      </element>
-    </define>
     <define name="admonition">
       <element name="admonition">
         <attribute name="type">
@@ -117,24 +105,6 @@
         </optional>
       </element>
     </define>
-    <define name="bibitem">
-      <element name="bibitem">
-        <attribute name="id">
-          <data type="ID"/>
-        </attribute>
-        <optional>
-          <attribute name="hidden">
-            <data type="boolean"/>
-          </attribute>
-        </optional>
-        <optional>
-          <attribute name="suppress_identifier">
-            <data type="boolean"/>
-          </attribute>
-        </optional>
-        <ref name="BibliographicItem"/>
-      </element>
-    </define>
     <define name="section-title">
       <element name="title">
         <zeroOrMore>
@@ -248,42 +218,6 @@
         <ref name="PureTextElement"/>
       </oneOrMore>
     </define>
-    <define name="localityStack">
-      <element name="localityStack">
-        <optional>
-          <attribute name="connective">
-            <choice>
-              <value>and</value>
-              <value>or</value>
-              <value>from</value>
-              <value>to</value>
-              <value/>
-            </choice>
-          </attribute>
-        </optional>
-        <zeroOrMore>
-          <ref name="locality"/>
-        </zeroOrMore>
-      </element>
-    </define>
-    <define name="sourceLocalityStack">
-      <element name="sourceLocalityStack">
-        <optional>
-          <attribute name="connective">
-            <choice>
-              <value>and</value>
-              <value>or</value>
-              <value>from</value>
-              <value>to</value>
-              <value/>
-            </choice>
-          </attribute>
-        </optional>
-        <zeroOrMore>
-          <ref name="sourceLocality"/>
-        </zeroOrMore>
-      </element>
-    </define>
     <define name="ul">
       <element name="ul">
         <attribute name="id">
@@ -827,21 +761,6 @@
         </zeroOrMore>
       </element>
     </define>
-    <define name="BibDataExtensionType">
-      <ref name="doctype"/>
-      <optional>
-        <ref name="docsubtype"/>
-      </optional>
-      <optional>
-        <ref name="editorialgroup"/>
-      </optional>
-      <zeroOrMore>
-        <ref name="ics"/>
-      </zeroOrMore>
-      <zeroOrMore>
-        <ref name="structuredidentifier"/>
-      </zeroOrMore>
-    </define>
     <!-- TitleType = text -->
     <define name="sections">
       <element name="sections">
@@ -881,7 +800,7 @@
           <ref name="BasicBlock"/>
         </zeroOrMore>
         <zeroOrMore>
-          <ref name="bibitem"/>
+          <ref name="doc_bibitem"/>
           <zeroOrMore>
             <ref name="note"/>
           </zeroOrMore>
@@ -1219,6 +1138,24 @@
     </define>
   </include>
   <!-- end overrides -->
+  <define name="doc_bibitem">
+    <element name="bibitem">
+      <attribute name="id">
+        <data type="ID"/>
+      </attribute>
+      <optional>
+        <attribute name="hidden">
+          <data type="boolean"/>
+        </attribute>
+      </optional>
+      <optional>
+        <attribute name="suppress_identifier">
+          <data type="boolean"/>
+        </attribute>
+      </optional>
+      <ref name="BibliographicItem"/>
+    </element>
+  </define>
   <define name="image" combine="choice">
     <element name="svg">
       <oneOrMore>
@@ -1237,14 +1174,6 @@
       <value>tag</value>
     </choice>
   </define>
-  <define name="docsubtype">
-    <element name="subdoctype">
-      <ref name="DocumentSubtype"/>
-    </element>
-  </define>
-  <define name="DocumentSubtype">
-    <text/>
-  </define>
   <define name="colgroup">
     <element name="colgroup">
       <oneOrMore>
@@ -1606,45 +1535,6 @@
       </choice>
     </element>
   </define>
-  <define name="editorialgroup">
-    <element name="editorialgroup">
-      <oneOrMore>
-        <ref name="technical-committee"/>
-      </oneOrMore>
-    </element>
-  </define>
-  <define name="technical-committee">
-    <element name="technical-committee">
-      <ref name="IsoWorkgroup"/>
-    </element>
-  </define>
-  <define name="IsoWorkgroup">
-    <optional>
-      <attribute name="number"/>
-    </optional>
-    <optional>
-      <attribute name="type"/>
-    </optional>
-    <optional>
-      <attribute name="identifier"/>
-    </optional>
-    <optional>
-      <attribute name="prefix"/>
-    </optional>
-    <text/>
-  </define>
-  <define name="ics">
-    <element name="ics">
-      <element name="code">
-        <text/>
-      </element>
-      <optional>
-        <element name="text">
-          <text/>
-        </element>
-      </optional>
-    </element>
-  </define>
   <define name="standard-document">
     <element name="standard-document">
       <attribute name="version"/>
@@ -2475,71 +2365,6 @@
       </optional>
     </element>
   </define>
-  <define name="structuredidentifier">
-    <element name="structuredidentifier">
-      <optional>
-        <attribute name="type"/>
-      </optional>
-      <oneOrMore>
-        <element name="agency">
-          <text/>
-        </element>
-      </oneOrMore>
-      <optional>
-        <element name="class">
-          <text/>
-        </element>
-      </optional>
-      <element name="docnumber">
-        <text/>
-      </element>
-      <optional>
-        <element name="partnumber">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="edition">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="version">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="supplementtype">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="supplementnumber">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="amendment">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="corrigendum">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="language">
-          <text/>
-        </element>
-      </optional>
-      <optional>
-        <element name="year">
-          <text/>
-        </element>
-      </optional>
-    </element>
-  </define>
   <define name="term-clause">
     <element name="clause">
       <optional>
@@ -2813,4 +2638,7 @@
       </attribute>
     </element>
   </define>
+  <start>
+    <ref name="standard-document"/>
+  </start>
 </grammar>
diff --git a/lib/metanorma/ribose/relaton-ribose.rng b/lib/metanorma/ribose/relaton-ribose.rng
new file mode 100644
index 0000000..0e95117
--- /dev/null
+++ b/lib/metanorma/ribose/relaton-ribose.rng
@@ -0,0 +1,58 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<grammar xmlns="http://relaxng.org/ns/structure/1.0">
+  <include href="biblio-standoc.rng">
+    <define name="DocumentType">
+      <choice>
+        <value>policy-and-procedures</value>
+        <value>best-practices</value>
+        <value>supporting-document</value>
+        <value>report</value>
+        <value>legal</value>
+        <value>directives</value>
+        <value>proposal</value>
+        <value>standard</value>
+      </choice>
+    </define>
+    <define name="editorialgroup">
+      <element name="editorialgroup">
+        <oneOrMore>
+          <ref name="committee"/>
+        </oneOrMore>
+      </element>
+    </define>
+    <define name="BibDataExtensionType">
+      <optional>
+        <attribute name="schema-version"/>
+      </optional>
+      <optional>
+        <ref name="doctype"/>
+      </optional>
+      <optional>
+        <ref name="docsubtype"/>
+      </optional>
+      <ref name="editorialgroup"/>
+      <zeroOrMore>
+        <ref name="ics"/>
+      </zeroOrMore>
+      <optional>
+        <ref name="security"/>
+      </optional>
+    </define>
+  </include>
+  <define name="committee">
+    <element name="committee">
+      <attribute name="type">
+        <choice>
+          <value>technical</value>
+          <value>provisional</value>
+        </choice>
+      </attribute>
+      <text/>
+    </element>
+  </define>
+  <define name="security">
+    <element name="security">
+      <text/>
+    </element>
+  </define>
+</grammar>
diff --git a/lib/metanorma/ribose/rsd.rng b/lib/metanorma/ribose/rsd.rng
index 414794b..e82f639 100644
--- a/lib/metanorma/ribose/rsd.rng
+++ b/lib/metanorma/ribose/rsd.rng
@@ -5,61 +5,12 @@
     we cannot have a new default namespace: we will end up with a grammar with two different
     namespaces, one for isostandard and one for csand additions. And we do not want that.
   -->
+  <include href="relaton-ribose.rng"/>
   <include href="isodoc.rng">
     <start>
       <ref name="rsd-standard"/>
     </start>
-    <define name="DocumentType">
-      <choice>
-        <value>policy-and-procedures</value>
-        <value>best-practices</value>
-        <value>supporting-document</value>
-        <value>report</value>
-        <value>legal</value>
-        <value>directives</value>
-        <value>proposal</value>
-        <value>standard</value>
-      </choice>
-    </define>
-    <define name="editorialgroup">
-      <element name="editorialgroup">
-        <oneOrMore>
-          <ref name="committee"/>
-        </oneOrMore>
-      </element>
-    </define>
-    <define name="BibDataExtensionType">
-      <optional>
-        <ref name="doctype"/>
-      </optional>
-      <optional>
-        <ref name="docsubtype"/>
-      </optional>
-      <ref name="editorialgroup"/>
-      <zeroOrMore>
-        <ref name="ics"/>
-      </zeroOrMore>
-      <optional>
-        <ref name="security"/>
-      </optional>
-    </define>
   </include>
-  <define name="committee">
-    <element name="committee">
-      <attribute name="type">
-        <choice>
-          <value>technical</value>
-          <value>provisional</value>
-        </choice>
-      </attribute>
-      <text/>
-    </element>
-  </define>
-  <define name="security">
-    <element name="security">
-      <text/>
-    </element>
-  </define>
   <define name="rsd-standard">
     <element name="rsd-standard">
       <attribute name="version"/>