diff --git a/include/arm/sa11x0/gpclk.h b/include/arm/sa11x0/gpclk.h
index 4012daef..f8fb5fa8 100644
--- a/include/arm/sa11x0/gpclk.h
+++ b/include/arm/sa11x0/gpclk.h
@@ -24,6 +24,8 @@
  * Documentation:
  * [1] Intel Corporation, "Intel StrongARM SA-1110 Microprocessor
  *     Developer's Manual", October 2001, Order Number: 278240-004
+ * [2] Intel Corporation, "Intel StrongARM SA-1110 Microprocessor
+ *     Specification Update", December 2001, Order Number: 278259-023
  *
  */
 
diff --git a/include/arm/sa11x0/udc.h b/include/arm/sa11x0/udc.h
index 946ff9d8..ef46ae54 100644
--- a/include/arm/sa11x0/udc.h
+++ b/include/arm/sa11x0/udc.h
@@ -24,6 +24,8 @@
  * Documentation:
  * [1] Intel Corporation, "Intel StrongARM SA-1110 Microprocessor
  *     Developer's Manual", October 2001, Order Number: 278240-004
+ * [2] Intel Corporation, "Intel StrongARM SA-1110 Microprocessor
+ *     Specification Update", December 2001, Order Number: 278259-023
  *
  */