diff --git a/cl-intel4004.asd b/cl-intel4004.asd
index dd1d53d..512268e 100644
--- a/cl-intel4004.asd
+++ b/cl-intel4004.asd
@@ -1,6 +1,6 @@
 (defsystem "cl-intel4004"
   :author "Emre Akan"
-  :description ""
+  :description "Intel 4004 emulator"
   :license "GPL-3.0-or-later"
   :version "0.0.0"
   :pathname "src"
diff --git a/src/emulator.lisp b/src/emulator.lisp
index d10f30c..7a60bff 100644
--- a/src/emulator.lisp
+++ b/src/emulator.lisp
@@ -1,4 +1,6 @@
 #||
+Copyright (C) 2026 Emre Akan
+
 This file is part of cl-intel4004.
 
 cl-intel4004 is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
diff --git a/src/package.lisp b/src/package.lisp
index e8e6b02..7db6395 100644
--- a/src/package.lisp
+++ b/src/package.lisp
@@ -1,4 +1,6 @@
 #||
+Copyright (C) 2026 Emre Akan
+
 This file is part of cl-intel4004.
 
 cl-intel4004 is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.