diff --git a/schema/edxml.rng b/schema/edxml.rng
index 463ad38b3f8915fa8cbc6ff385d01ba83f219b7e..f5389ff4d540b664a30dd64a56ca0669369cab3f 100644
--- a/schema/edxml.rng
+++ b/schema/edxml.rng
@@ -16,6 +16,19 @@
         <attribute name="ana"/>
     </define>
 
+    <define name="attr.cert">
+        <attribute name="cert">            
+            <list>                
+                <choice>
+                    <value>high</value>
+                    <a:documentation>(default) Die Aussage ist sicher und lässt sich zweifelsfrei belegen.</a:documentation>
+                    <value>low</value>
+                    <a:documentation>Die Aussage ist unsicher. Sie lässt sich nicht zweifelsfrei belegen.</a:documentation>
+                </choice>
+            </list>
+        </attribute>
+    </define>
+
     <define name="attr.copy">
         <attribute name="copy">
             <data type="boolean"/>
@@ -324,15 +337,8 @@
                 <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>
@@ -613,6 +619,53 @@
         </element>
     </define>
 
+    <define name="elem.relations">
+        <element name="relations">
+            <element name="head">
+                <text/>
+            </element>
+            <zeroOrMore>
+                <ref name="elem.relation"/>
+            </zeroOrMore>
+        </element>
+    </define>
+
+    <define name="elem.relation">
+        <element name="relation">
+            <attribute name="type"/>
+            <attribute name="source">
+                <data type="anyURI"/>
+                <sch:pattern>
+                    <sch:rule context="edxml:relation/@source">
+                        <sch:let name="id" value="substring-after(., '#')"/>
+                        <sch:assert test="//*[@xml:id = $id]" role="error">(ID '<sch:value-of
+                                select="$id"/>' gibt's nicht!): Die ID in @<sch:name/> gibt es in
+                            diesem Dokument nicht!</sch:assert>
+                    </sch:rule>
+                </sch:pattern>
+            </attribute>
+            <attribute name="target">
+                <data type="anyURI"/>
+                <sch:pattern>
+                    <sch:rule context="edxml:relation/@target">
+                        <sch:let name="id" value="substring-after(., '#')"/>
+                        <sch:assert test="//*[@xml:id = $id]" role="error">(ID '<sch:value-of
+                                select="$id"/>' gibt's nicht!): Die ID in @<sch:name/> gibt es in
+                            diesem Dokument nicht!</sch:assert>
+                    </sch:rule>
+                </sch:pattern>
+            </attribute>
+            <text/>
+        </element>
+    </define>
+
+    <define name="elem.ref">
+        <element name="ref">
+            <attribute name="target"/>
+            <text/>
+        </element>
+    </define>
+
     <define name="elem.phr">
         <element name="phr">
             <optional>
@@ -892,10 +945,15 @@
     <define name="elem.translation">
         <element name="translation">
             <ref name="attr.xml.lang"/>
+            <optional>
+                <ref name="attr.cert"/>
+            </optional>
             <interleave>
                 <!--<ref name="group.inline.elements"/>-->
                 <ref name="model.philological.translit"/>
-                <ref name="elem.hi"/>
+                <zeroOrMore>
+                    <ref name="elem.hi"/>
+                </zeroOrMore>
                 <text/>
             </interleave>
         </element>
@@ -1006,6 +1064,9 @@
             <optional>
                 <ref name="attr.ana"/>
             </optional>
+            <optional>
+                <ref name="attr.cert"/>
+            </optional>
             <optional>
                 <ref name="attr.corresp"/>
             </optional>
@@ -1575,16 +1636,16 @@
             </optional>
         </element>
     </define>
-    
+
     <define name="elem.tei.availability">
         <element name="tei:availability">
-            <ref name="elem.tei.licence"></ref>
+            <ref name="elem.tei.licence"/>
         </element>
     </define>
-    
+
     <define name="elem.tei.licence">
         <element name="tei:licence">
-            <ref name="attr.tei.target"></ref>
+            <ref name="attr.tei.target"/>
         </element>
     </define>
 
@@ -1593,7 +1654,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1611,7 +1679,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1620,7 +1695,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1629,7 +1711,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1638,7 +1727,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1647,7 +1743,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1656,7 +1759,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1668,7 +1778,15 @@
             <optional>
                 <ref name="attr.tei.degree"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
+            <!-- Hier könnte man noch eine Schematron-Validierung einbauen: Wenn ein ancestor-Element surface/textBlock/transcription ist, dann darf tei.damage kein text() enthalten, sondern nur elem.g -->
         </element>
     </define>
 
@@ -1677,7 +1795,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1686,7 +1811,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1695,7 +1827,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1704,7 +1843,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1713,7 +1859,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1722,7 +1875,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1731,7 +1891,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1740,7 +1907,14 @@
             <optional>
                 <ref name="attr.xml.id"/>
             </optional>
-            <text/>
+            <oneOrMore>
+                <optional>
+                    <ref name="elem.g"/>
+                </optional>
+                <optional>
+                    <text/>
+                </optional>
+            </oneOrMore>
         </element>
     </define>
 
@@ -1753,9 +1927,9 @@
             </choice>
         </attribute>
     </define>
-    
+
     <define name="attr.tei.target">
-        <attribute name="target"/>        
+        <attribute name="target"/>
     </define>
 
 </grammar>