diff --git a/ref.xsl b/ref.xsl
index c34cd351..9861a133 100644
--- a/ref.xsl
+++ b/ref.xsl
@@ -30,7 +30,7 @@ THE SOFTWARE.
 
 <xsl:stylesheet xmlns:xsl='http://www.w3.org/1999/XSL/Transform' version='1.0'>
 
-  <xsl:output method='xml' indent='yes'/>
+  <xsl:output method='xml' indent='yes' version='1.0' encoding='UTF-8'/>
 
   <xsl:template match='/'>
     <reference>