diff --git a/src/mame/drivers/a6809.cpp b/src/mame/drivers/a6809.cpp
index 07b189ee6b3..93b2e89ad2f 100644
--- a/src/mame/drivers/a6809.cpp
+++ b/src/mame/drivers/a6809.cpp
@@ -1,5 +1,5 @@
 // license:BSD-3-Clause
-// copyright-holders:Robbbert and unknown others
+// copyright-holders:Robbbert
 /***************************************************************************
 
     Acorn 6809
diff --git a/src/mame/drivers/trs80.cpp b/src/mame/drivers/trs80.cpp
index 434b4ab3e62..6e5e7ab59ef 100644
--- a/src/mame/drivers/trs80.cpp
+++ b/src/mame/drivers/trs80.cpp
@@ -1,5 +1,7 @@
 // license:BSD-3-Clause
-// copyright-holders:Robbbert and unknown others
+// copyright-holders:Jurgen Buchmueller, Robbbert
+// Originally written in MESS 0.1 by Jurgen Buchmueller.
+// Substantially rewritten by Robbbert in 2008, many new clones added
 /***************************************************************************
 TRS80 memory map