lib/asciidoctor/bipm/bipm.rng in metanorma-bipm-1.0.0 vs lib/asciidoctor/bipm/bipm.rng in metanorma-bipm-1.0.1

@@ -45,10 +45,15 @@
         <optional>
           <attribute name="nosee">
             <data type="boolean"/>
           </attribute>
         </optional>
+        <optional>
+          <attribute name="nopage">
+            <data type="boolean"/>
+          </attribute>
+        </optional>
         <text/>
       </element>
     </define>
     <define name="Clause-Section">
       <optional>
@@ -336,10 +341,12 @@
         <ref name="termdocsource"/>
       </zeroOrMore>
       <optional>
         <ref name="boilerplate"/>
       </optional>
-      <ref name="preface"/>
+      <optional>
+        <ref name="preface"/>
+      </optional>
       <oneOrMore>
         <ref name="sections"/>
       </oneOrMore>
       <zeroOrMore>
         <ref name="annex"/>