diff --git a/schema/edxml.rng b/schema/edxml.rng
index 8d183acf87322b40ce9dc12eea693bb3e029dcbe..e52874f6b86e49947b9e2a6465ecf971c4b5c2f8 100644
--- a/schema/edxml.rng
+++ b/schema/edxml.rng
@@ -13,6 +13,14 @@
     <define name="attr.ana">
         <attribute name="ana"/>
     </define>
+    
+    <define name="attr.cert">
+        <attribute name="cert">
+            <list>
+                <value>uncertain</value>
+            </list>
+        </attribute>
+    </define>
 
     <define name="attr.copy">
         <attribute name="copy">
@@ -302,15 +310,8 @@
                 <ref name="attr.ana"/>
             </optional>
             <optional>
-                <attribute name="cert">
-                    <list>
-                        <value>uncertain</value>
-                    </list>
-                </attribute>
+                <ref name="attr.cert"/>
             </optional>
-            <zeroOrMore>
-                <ref name="model.transcriptional"/>
-            </zeroOrMore>
             <text/>
         </element>
     </define>
@@ -952,6 +953,9 @@
             <optional>
                 <ref name="attr.ana"/>
             </optional>
+            <optional>
+                <ref name="attr.cert"/>
+            </optional>
             <optional>
                 <ref name="attr.corresp"/>
             </optional>
@@ -1514,7 +1518,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
     
@@ -1532,7 +1539,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>            
         </element>
     </define>
 
@@ -1541,7 +1551,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore> 
         </element>
     </define>
 
@@ -1550,7 +1563,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1559,7 +1575,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1568,7 +1587,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1577,7 +1599,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1589,7 +1614,10 @@
             <optional>
                 <ref name="attr.tei.degree"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1598,7 +1626,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1607,7 +1638,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1616,7 +1650,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1625,7 +1662,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1634,7 +1674,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1643,7 +1686,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1652,7 +1698,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1661,7 +1710,10 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <ref name="elem.g"></ref>
+                <text/>
+            </oneOrMore>
         </element>
     </define>