diff --git a/poky/documentation/ref-manual/ref-system-requirements.xml b/poky/documentation/ref-manual/ref-system-requirements.xml
index 7a11ec2..43e217c 100644
--- a/poky/documentation/ref-manual/ref-system-requirements.xml
+++ b/poky/documentation/ref-manual/ref-system-requirements.xml
@@ -1,6 +1,7 @@
 <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
 [<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
 
 <chapter id='ref-manual-system-requirements'>
 <title>System Requirements</title>