diff --git a/grammars/ieee.rnc b/grammars/ieee.rnc
index 8ab188c..5fd5c78 100644
--- a/grammars/ieee.rnc
+++ b/grammars/ieee.rnc
@@ -3,7 +3,17 @@
 # namespaces, one for isostandard and one for csand additions. And we do not want that.
 
 include "relaton-ieee.rnc" { }
-include "isodoc.rnc" { start = ieee-standard }
+include "isodoc.rnc" { 
+
+start = ieee-standard 
+
+sections =
+  element sections {
+    note?,
+    ( clause | terms | term-clause | definitions | floating-title )+
+} 
+
+}
 
 ieee-standard =
   element ieee-standard {
diff --git a/grammars/ieee.rng b/grammars/ieee.rng
index c4ef078..683eec5 100644
--- a/grammars/ieee.rng
+++ b/grammars/ieee.rng
@@ -10,6 +10,22 @@
     <start>
       <ref name="ieee-standard"/>
     </start>
+    <define name="sections">
+      <element name="sections">
+        <optional>
+          <ref name="note"/>
+        </optional>
+        <oneOrMore>
+          <choice>
+            <ref name="clause"/>
+            <ref name="terms"/>
+            <ref name="term-clause"/>
+            <ref name="definitions"/>
+            <ref name="floating-title"/>
+          </choice>
+        </oneOrMore>
+      </element>
+    </define>
   </include>
   <define name="ieee-standard">
     <element name="ieee-standard">