diff --git a/AlsaMixer.app/AMixer/AChannel.cc b/AlsaMixer.app/AMixer/AChannel.cc
index 745bf08..bc2aeef 100644
--- a/AlsaMixer.app/AMixer/AChannel.cc
+++ b/AlsaMixer.app/AMixer/AChannel.cc
@@ -1,4 +1,8 @@
-// AChannel.cc, Petr Hlavka, 2004
+// AChannel.cc
+//
+// Copyright (C) 2004, Petr Hlavka
+//
+// SPDX-License-Identifier: GPL-2.0+
 
 #include "AMixer.h"
 #include "AItem.h"
diff --git a/AlsaMixer.app/AMixer/AChannel.h b/AlsaMixer.app/AMixer/AChannel.h
index 57ad075..bc1b962 100644
--- a/AlsaMixer.app/AMixer/AChannel.h
+++ b/AlsaMixer.app/AMixer/AChannel.h
@@ -1,4 +1,8 @@
-// AChannel.h, Petr Hlavka, 2004
+// AChannel.h
+//
+// Copyright (C) 2004, Petr Hlavka
+//
+// SPDX-License-Identifier: GPL-2.0+
 
 #ifndef ACHANNEL_H
 #define ACHANNEL_H
diff --git a/AlsaMixer.app/AMixer/AItem.cc b/AlsaMixer.app/AMixer/AItem.cc
index 7272268..d8e4c7b 100644
--- a/AlsaMixer.app/AMixer/AItem.cc
+++ b/AlsaMixer.app/AMixer/AItem.cc
@@ -1,4 +1,8 @@
-// AItem.cc, Petr Hlavka, 2004
+// AItem.cc
+//
+// Copyright (C) 2004, Petr Hlavka
+//
+// SPDX-License-Identifier: GPL-2.0+
 
 #include "AItem.h"
 #include "AMixer.h"
diff --git a/AlsaMixer.app/AMixer/AItem.h b/AlsaMixer.app/AMixer/AItem.h
index 93e5aa0..a88c735 100644
--- a/AlsaMixer.app/AMixer/AItem.h
+++ b/AlsaMixer.app/AMixer/AItem.h
@@ -1,4 +1,8 @@
-// AItem.h, Petr Hlavka, 2004
+// AItem.h
+//
+// Copyright (C) 2004, Petr Hlavka
+//
+// SPDX-License-Identifier: GPL-2.0+
 
 #ifndef AITEM_H
 #define AITEM_H
diff --git a/AlsaMixer.app/AMixer/AMixer.cc b/AlsaMixer.app/AMixer/AMixer.cc
index dbe45c2..ea9f70d 100644
--- a/AlsaMixer.app/AMixer/AMixer.cc
+++ b/AlsaMixer.app/AMixer/AMixer.cc
@@ -1,4 +1,8 @@
-// AMixer.cc, Petr Hlavka, 2004
+// AMixer.cc
+//
+// Copyright (C) 2004, Petr Hlavka
+//
+// SPDX-License-Identifier: GPL-2.0+
 
 #include "AMixer.h"
 #include "AItem.h"
diff --git a/AlsaMixer.app/AMixer/AMixer.h b/AlsaMixer.app/AMixer/AMixer.h
index 16c2960..2376dd1 100644
--- a/AlsaMixer.app/AMixer/AMixer.h
+++ b/AlsaMixer.app/AMixer/AMixer.h
@@ -1,4 +1,8 @@
-// AMixer.h, Petr Hlavka, 2004
+// AMixer.h
+//
+// Copyright (C) 2004, Petr Hlavka
+//
+// SPDX-License-Identifier: GPL-2.0+
 
 #ifndef AMIXER_H
 #define AMIXER_H
diff --git a/AlsaMixer.app/COPYING b/AlsaMixer.app/COPYING
index d159169..23b993b 100644
--- a/AlsaMixer.app/COPYING
+++ b/AlsaMixer.app/COPYING
@@ -337,3 +337,12 @@ proprietary programs.  If your program is a subroutine library, you may
 consider it more useful to permit linking proprietary applications with the
 library.  If this is what you want to do, use the GNU Lesser General
 Public License instead of this License.
+
+---------------------------------------------------------------------------
+Note:
+Individual files contain the following tag instead of the full license text.
+
+    SPDX-License-Identifier:    GPL-2.0+
+
+This enables machine processing of license information based on the SPDX
+License Identifiers that are here available: http://spdx.org/licenses/
diff --git a/AlsaMixer.app/Main.cc b/AlsaMixer.app/Main.cc
index 4f467de..c7f185b 100644
--- a/AlsaMixer.app/Main.cc
+++ b/AlsaMixer.app/Main.cc
@@ -1,7 +1,8 @@
 //
-//  Mixer.app
+//  Mixer.app / AlsaMixer.app
 //
 //  Copyright (c) 1998-2002 Per Liden
+//  Copyright (C) 2004, Petr Hlavka
 //
 //  This program is free software; you can redistribute it and/or modify
 //  it under the terms of the GNU General Public License as published by
diff --git a/AlsaMixer.app/Makefile b/AlsaMixer.app/Makefile
index 14f510c..23dcfe7 100644
--- a/AlsaMixer.app/Makefile
+++ b/AlsaMixer.app/Makefile
@@ -1,6 +1,10 @@
 #
-# Mixer.app Makefile
+# AlsaMixer.app Makefile
 #
+# Copyright (c) 1998-2002 Per Liden
+# Copyright (C) 2004, Petr Hlavka
+#
+# SPDX-License-Identifier: GPL-2.0+
 
 DESTDIR =
 GNUSTEP_BINDIR = /usr/local/GNUstep/Apps/AlsaMixer.app
diff --git a/AlsaMixer.app/Mixer.cc b/AlsaMixer.app/Mixer.cc
index 66ebe6e..85cfe71 100644
--- a/AlsaMixer.app/Mixer.cc
+++ b/AlsaMixer.app/Mixer.cc
@@ -1,7 +1,8 @@
 //
-//  Mixer.app
+//  Mixer.app / AlsaMixer.app
 //
 //  Copyright (c) 1998-2002 Per Liden
+//  Copyright (C) 2004, Petr Hlavka
 //
 //  This program is free software; you can redistribute it and/or modify
 //  it under the terms of the GNU General Public License as published by
diff --git a/AlsaMixer.app/Mixer.h b/AlsaMixer.app/Mixer.h
index 187a7fb..6e226a3 100644
--- a/AlsaMixer.app/Mixer.h
+++ b/AlsaMixer.app/Mixer.h
@@ -1,7 +1,8 @@
 //
-//  Mixer.app
+//  Mixer.app / AlsaMixer.app
 //
 //  Copyright (c) 1998-2002 Per Liden
+//  Copyright (C) 2004, Petr Hlavka
 //
 //  This program is free software; you can redistribute it and/or modify
 //  it under the terms of the GNU General Public License as published by
diff --git a/AlsaMixer.app/olddoc/ChangeLog.Mixer.app b/AlsaMixer.app/olddoc/ChangeLog.Mixer.app
index 741863f..74a3fef 100644
--- a/AlsaMixer.app/olddoc/ChangeLog.Mixer.app
+++ b/AlsaMixer.app/olddoc/ChangeLog.Mixer.app
@@ -3,7 +3,7 @@ Version		Description
 1.8.0		- Released 2002-09-15
 		- Now supports all mixer sources. NOTE! The source names have
 		  been changed. See "Mixer.app -h".
-		- Added alternative skin submitted by Hans D. <barross@web.de>.
+		- Added alternative skin submitted by Hans Dembinski <barross@web.de>.
 		- Fixed warnings when compiling with GCC 3.2.
 		- Added OpenBSD support (thanks to ptiJo <ptiJo@noos.fr>).