diff --git a/source/fltkui/audiomanager.cpp b/source/fltkui/audiomanager.cpp
index eb5edf1..81006c6 100644
--- a/source/fltkui/audiomanager.cpp
+++ b/source/fltkui/audiomanager.cpp
@@ -2,6 +2,7 @@
  * Nestopia UE
  *
  * Copyright (C) 2012-2024 R. Danbrook
+ * Copyright (C) 2020-2024 Rupert Carmichael
  *
  * 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/source/fltkui/fltkui.cpp b/source/fltkui/fltkui.cpp
index f0eee8d..34dcb55 100644
--- a/source/fltkui/fltkui.cpp
+++ b/source/fltkui/fltkui.cpp
@@ -443,7 +443,9 @@ void FltkUi::about(Fl_Widget *w, void *data) {
     Fl_Box text2(0, 208, 460, UI_SPACING, "Cycle-Accurate Nintendo Entertainment System Emulator");
 
     Fl_Box text3(0, 256, 460, UI_SPACING,
-                 "FLTK Frontend\n(c) 2012-2024, R. Danbrook");
+                 "FLTK Frontend\n(c) 2012-2024, R. Danbrook\n\n"
+                 "Portions derived from The Jolly Good Reference Frontend\n"
+                 "(c) 2020-2024, Rupert Carmichael\n");
     text3.labelsize(10);
 
     Fl_Box text4(0, 320, 460, UI_SPACING,
diff --git a/source/fltkui/inputmanager.cpp b/source/fltkui/inputmanager.cpp
index c6783f9..542341f 100644
--- a/source/fltkui/inputmanager.cpp
+++ b/source/fltkui/inputmanager.cpp
@@ -2,6 +2,7 @@
  * Nestopia UE
  *
  * Copyright (C) 2012-2024 R. Danbrook
+ * Copyright (C) 2020-2024 Rupert Carmichael
  *
  * 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/source/fltkui/videomanager.cpp b/source/fltkui/videomanager.cpp
index ed99710..5e73f6d 100644
--- a/source/fltkui/videomanager.cpp
+++ b/source/fltkui/videomanager.cpp
@@ -2,6 +2,7 @@
  * Nestopia UE
  *
  * Copyright (C) 2012-2024 R. Danbrook
+ * Copyright (C) 2020-2024 Rupert Carmichael
  *
  * 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