diff --git a/IntelFrameworkPkg/Include/Ppi/ReadOnlyVariable.h b/IntelFrameworkPkg/Include/Ppi/ReadOnlyVariable.h
index 077293749d..c39e0e7e5d 100644
--- a/IntelFrameworkPkg/Include/Ppi/ReadOnlyVariable.h
+++ b/IntelFrameworkPkg/Include/Ppi/ReadOnlyVariable.h
@@ -16,6 +16,9 @@
   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
+  @par Revision Reference:
+  This PPI is defined in PEI CIS
+  Version 0.91.
 **/
 
 #ifndef __PEI_READ_ONLY_VARIABLE_PPI_H__