diff --git a/xml/api/crm_attribute-2.34.rng b/xml/api/crm_attribute-2.34.rng
index 6c040eaeff..8e84f0b112 100644
--- a/xml/api/crm_attribute-2.34.rng
+++ b/xml/api/crm_attribute-2.34.rng
@@ -1,32 +1,33 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <grammar xmlns="http://relaxng.org/ns/structure/1.0"
          datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
 
     <start>
-        <ref name="element-crm_attribute"/>
+        <ref name="element-crm_attribute" />
     </start>
 
     <define name="element-crm_attribute">
         <choice>
             <zeroOrMore>
                 <ref name="element-attribute" />
             </zeroOrMore>
+            <externalRef href="options-2.34.rng" />
         </choice>
     </define>
 
     <define name="element-attribute">
         <element name="attribute">
             <optional>
                 <attribute name="scope"> <text /> </attribute>
             </optional>
             <optional>
                 <attribute name="id"> <text /> </attribute>
             </optional>
             <attribute name="name"> <text /> </attribute>
             <attribute name="value"> <text /> </attribute>
             <optional>
                 <attribute name="host"> <text /> </attribute>
             </optional>
         </element>
     </define>
 </grammar>