diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 74c528f..f6603d5 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -13,6 +13,11 @@
  *          <em>ISO/IEC 18033-2:2006: Information technology -- Security
  *          techniques -- Encryption algorithms -- Part 2: Asymmetric
  *          ciphers</em>.
+ *
+ *          The AES-XTS block mode is standardized by NIST SP 800-38E
+ *          <https://nvlpubs.nist.gov/nistpubs/legacy/sp/nistspecialpublication800-38e.pdf>
+ *          and described in detail by IEEE P1619
+ *          <https://ieeexplore.ieee.org/servlet/opac?punumber=4375278>.
  */
 
 /*  Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved.