diff --git a/COPYING.txt b/COPYING.txt
new file mode 100644
index 0000000..d7d7cde
--- /dev/null
+++ b/COPYING.txt
@@ -0,0 +1,17 @@
+Copyright (C) 2015-2022 a dinosaur
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
diff --git a/src/tmx2gba.cpp b/src/tmx2gba.cpp
index cd0a35d..61a6822 100644
--- a/src/tmx2gba.cpp
+++ b/src/tmx2gba.cpp
@@ -1,24 +1,4 @@
-/* tmx2gba.cpp
-
-  Copyright (C) 2015-2022 a dinosaur
-
-  This software is provided 'as-is', without any express or implied
-  warranty.  In no event will the authors be held liable for any damages
-  arising from the use of this software.
-
-  Permission is granted to anyone to use this software for any purpose,
-  including commercial applications, and to alter it and redistribute it
-  freely, subject to the following restrictions:
-
-  1. The origin of this software must not be misrepresented; you must not
-     claim that you wrote the original software. If you use this software
-     in a product, an acknowledgment in the product documentation would be
-     appreciated but is not required.
-  2. Altered source versions must be plainly marked as such, and must not be
-     misrepresented as being the original software.
-  3. This notice may not be removed or altered from any source distribution.
-
-*/
+/* tmx2gba.cpp - Copyright (C) 2015-2022 a dinosaur (zlib, see COPYING.txt) */
 
 #include "tmxreader.hpp"
 #include "tmxlayer.hpp"
diff --git a/src/tmxlayer.hpp b/src/tmxlayer.hpp
index 81ed802..e25484a 100644
--- a/src/tmxlayer.hpp
+++ b/src/tmxlayer.hpp
@@ -1,24 +1,4 @@
-/* tmxlayer.cpp
-
-  Copyright (C) 2015-2022 a dinosaur
-
-  This software is provided 'as-is', without any express or implied
-  warranty.  In no event will the authors be held liable for any damages
-  arising from the use of this software.
-
-  Permission is granted to anyone to use this software for any purpose,
-  including commercial applications, and to alter it and redistribute it
-  freely, subject to the following restrictions:
-
-  1. The origin of this software must not be misrepresented; you must not
-     claim that you wrote the original software. If you use this software
-     in a product, an acknowledgment in the product documentation would be
-     appreciated but is not required.
-  2. Altered source versions must be plainly marked as such, and must not be
-     misrepresented as being the original software.
-  3. This notice may not be removed or altered from any source distribution.
-
-*/
+/* tmxlayer.hpp - Copyright (C) 2015-2022 a dinosaur (zlib, see COPYING.txt) */
 
 #ifndef TMXLAYER_H
 #define TMXLAYER_H
diff --git a/src/tmxobject.hpp b/src/tmxobject.hpp
index 55083bb..5b1e841 100644
--- a/src/tmxobject.hpp
+++ b/src/tmxobject.hpp
@@ -1,24 +1,4 @@
-/* tmxobject.cpp
-
-  Copyright (C) 2015-2022 a dinosaur
-
-  This software is provided 'as-is', without any express or implied
-  warranty.  In no event will the authors be held liable for any damages
-  arising from the use of this software.
-
-  Permission is granted to anyone to use this software for any purpose,
-  including commercial applications, and to alter it and redistribute it
-  freely, subject to the following restrictions:
-
-  1. The origin of this software must not be misrepresented; you must not
-     claim that you wrote the original software. If you use this software
-     in a product, an acknowledgment in the product documentation would be
-     appreciated but is not required.
-  2. Altered source versions must be plainly marked as such, and must not be
-     misrepresented as being the original software.
-  3. This notice may not be removed or altered from any source distribution.
-
-*/
+/* tmxobject.cpp - Copyright (C) 2015-2022 a dinosaur (zlib, see COPYING.txt) */
 
 #ifndef TMXOBJECT_H
 #define TMXOBJECT_H
diff --git a/src/tmxreader.cpp b/src/tmxreader.cpp
index a70a87f..e504e02 100644
--- a/src/tmxreader.cpp
+++ b/src/tmxreader.cpp
@@ -1,24 +1,4 @@
-/* tmxreader.cpp
-
-  Copyright (C) 2015-2022 a dinosaur
-
-  This software is provided 'as-is', without any express or implied
-  warranty.  In no event will the authors be held liable for any damages
-  arising from the use of this software.
-
-  Permission is granted to anyone to use this software for any purpose,
-  including commercial applications, and to alter it and redistribute it
-  freely, subject to the following restrictions:
-
-  1. The origin of this software must not be misrepresented; you must not
-     claim that you wrote the original software. If you use this software
-     in a product, an acknowledgment in the product documentation would be
-     appreciated but is not required.
-  2. Altered source versions must be plainly marked as such, and must not be
-     misrepresented as being the original software.
-  3. This notice may not be removed or altered from any source distribution.
-
-*/
+/* tmxreader.cpp - Copyright (C) 2015-2022 a dinosaur (zlib, see COPYING.txt) */
 
 #include "tmxreader.hpp"
 #include "tmxtileset.hpp"
diff --git a/src/tmxreader.hpp b/src/tmxreader.hpp
index 5baf2eb..b7be596 100644
--- a/src/tmxreader.hpp
+++ b/src/tmxreader.hpp
@@ -1,3 +1,5 @@
+/* tmxreader.hpp - Copyright (C) 2015-2022 a dinosaur (zlib, see COPYING.txt) */
+
 #ifndef TMXREADER_H
 #define TMXREADER_H
 
diff --git a/src/tmxtileset.hpp b/src/tmxtileset.hpp
index 2a31862..a79eb27 100644
--- a/src/tmxtileset.hpp
+++ b/src/tmxtileset.hpp
@@ -1,24 +1,4 @@
-/* tmxtileset.cpp
-
-  Copyright (C) 2015-2022 a dinosaur
-
-  This software is provided 'as-is', without any express or implied
-  warranty.  In no event will the authors be held liable for any damages
-  arising from the use of this software.
-
-  Permission is granted to anyone to use this software for any purpose,
-  including commercial applications, and to alter it and redistribute it
-  freely, subject to the following restrictions:
-
-  1. The origin of this software must not be misrepresented; you must not
-     claim that you wrote the original software. If you use this software
-     in a product, an acknowledgment in the product documentation would be
-     appreciated but is not required.
-  2. Altered source versions must be plainly marked as such, and must not be
-     misrepresented as being the original software.
-  3. This notice may not be removed or altered from any source distribution.
-
-*/
+/* tmxtileset.hpp - Copyright (C) 2015-2022 a dinosaur (zlib, see COPYING.txt) */
 
 #ifndef TMXTILESET_H
 #define TMXTILESET_H