diff --git a/sj3lib/level1.c b/sj3lib/level1.c
index 6fdc6d9..5ec0f61 100644
--- a/sj3lib/level1.c
+++ b/sj3lib/level1.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: MIT-open-group
+ * 
  * Copyright (c) 1991-1994  Sony Corporation
  * 
  * Permission is hereby granted, free of charge, to any person obtaining
@@ -24,16 +26,8 @@
  * shall not be used in advertising or otherwise to promote the sale, use
  * or other dealings in this Software without prior written authorization
  * from Sony Corporation.
- *
  */
 
-/*
- * $SonyRCSfile: level1.c,v $  
- * $SonyRevision: 1.4 $ 
- * $SonyDate: 1995/04/17 10:36:08 $
- *
- * $Id: level1.c,v 1.2 2004/07/20 15:55:43 hiroo Exp $
- */
 
 
 #include "sj_sysvdef.h" 
diff --git a/sj3lib/sj.c b/sj3lib/sj.c
index 1f8b61c..bf548ef 100644
--- a/sj3lib/sj.c
+++ b/sj3lib/sj.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: MIT-open-group
+ * 
  * Copyright (c) 1991-1994  Sony Corporation
  * 
  * Permission is hereby granted, free of charge, to any person obtaining
@@ -24,16 +26,8 @@
  * shall not be used in advertising or otherwise to promote the sale, use
  * or other dealings in this Software without prior written authorization
  * from Sony Corporation.
- *
  */
 
-/*
- * $SonyRCSfile: sj.c,v $  
- * $SonyRevision: 1.2 $ 
- * $SonyDate: 1994/12/09 11:27:09 $
- *
- * $Id$
- */
 
 
 #include <ctype.h>
diff --git a/sj3lib/sj3lib.h b/sj3lib/sj3lib.h
index 49ea6c0..5002cc9 100644
--- a/sj3lib/sj3lib.h
+++ b/sj3lib/sj3lib.h
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: MIT-open-group
+ * 
  * Copyright (c) 1991-1994  Sony Corporation
  * 
  * Permission is hereby granted, free of charge, to any person obtaining
@@ -24,16 +26,8 @@
  * shall not be used in advertising or otherwise to promote the sale, use
  * or other dealings in this Software without prior written authorization
  * from Sony Corporation.
- *
  */
 
-/*
- * $SonyRCSfile: sj3lib.h,v $  
- * $SonyRevision: 1.1 $ 
- * $SonyDate: 1994/06/03 08:03:57 $
- *
- * $Id$
- */
 
 #ifndef _SJ3LIB_H_
 #define _SJ3LIB_H_  1
diff --git a/sj3lib/string.c b/sj3lib/string.c
index b68044a..6dde75e 100644
--- a/sj3lib/string.c
+++ b/sj3lib/string.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: MIT-open-group
+ * 
  * Copyright (c) 1994  Sony Corporation
  * 
  * Permission is hereby granted, free of charge, to any person obtaining
@@ -24,14 +26,8 @@
  * shall not be used in advertising or otherwise to promote the sale, use
  * or other dealings in this Software without prior written authorization
  * from Sony Corporation.
- *
  */
 
-/*
- * $SonyRCSfile: string.c,v $  
- * $SonyRevision: 1.1 $ 
- * $SonyDate: 1994/06/03 08:03:58 $
- */