diff --git a/src/mod/asr_tts/mod_cepstral/mod_cepstral.c b/src/mod/asr_tts/mod_cepstral/mod_cepstral.c
index 35e8e1dd2b..9c673e1f0c 100644
--- a/src/mod/asr_tts/mod_cepstral/mod_cepstral.c
+++ b/src/mod/asr_tts/mod_cepstral/mod_cepstral.c
@@ -27,6 +27,9 @@
  *
  *
  * mod_cepstral.c -- Cepstral Interface
+ * 
+ * Some material based on the Cepstral Swift SDK, 
+ * Copyiright Cepstral LLC and used by permission
  *
  */
 #ifdef __ICC