diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index b0602dbd8..dd174d5ee 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -2,6 +2,7 @@
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *  Copyright (C) 2019  Eddie Hung <eddie@fpgeh.com>
  *
  *  Permission to use, copy, modify, and/or distribute this software for any
  *  purpose with or without fee is hereby granted, provided that the above
diff --git a/frontends/aiger/aigerparse.cc b/frontends/aiger/aigerparse.cc
index 45cacadb6..1302d03df 100644
--- a/frontends/aiger/aigerparse.cc
+++ b/frontends/aiger/aigerparse.cc
@@ -2,7 +2,7 @@
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
- *                      Eddie Hung <eddie@fpgeh.com>
+ *  Copyright (C) 2019  Eddie Hung <eddie@fpgeh.com>
  *
  *  Permission to use, copy, modify, and/or distribute this software for any
  *  purpose with or without fee is hereby granted, provided that the above
diff --git a/passes/techmap/abc9.cc b/passes/techmap/abc9.cc
index 9ea2a7014..17a5c0fe3 100644
--- a/passes/techmap/abc9.cc
+++ b/passes/techmap/abc9.cc
@@ -2,6 +2,7 @@
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *  Copyright (C) 2019  Eddie Hung <eddie@fpgeh.com>
  *
  *  Permission to use, copy, modify, and/or distribute this software for any
  *  purpose with or without fee is hereby granted, provided that the above