diff --git a/src/oaipmh_scythe/__init__.py b/src/oaipmh_scythe/__init__.py
index 3649bff..6ea59c7 100644
--- a/src/oaipmh_scythe/__init__.py
+++ b/src/oaipmh_scythe/__init__.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/src/oaipmh_scythe/exceptions.py b/src/oaipmh_scythe/exceptions.py
index 551c53a..1954d61 100644
--- a/src/oaipmh_scythe/exceptions.py
+++ b/src/oaipmh_scythe/exceptions.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/src/oaipmh_scythe/iterator.py b/src/oaipmh_scythe/iterator.py
index cd28fb8..4fd1487 100644
--- a/src/oaipmh_scythe/iterator.py
+++ b/src/oaipmh_scythe/iterator.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/src/oaipmh_scythe/models.py b/src/oaipmh_scythe/models.py
index bd26326..a102199 100644
--- a/src/oaipmh_scythe/models.py
+++ b/src/oaipmh_scythe/models.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/src/oaipmh_scythe/response.py b/src/oaipmh_scythe/response.py
index 5332dfe..cf799af 100644
--- a/src/oaipmh_scythe/response.py
+++ b/src/oaipmh_scythe/response.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/src/oaipmh_scythe/scythe.py b/src/oaipmh_scythe/scythe.py
index 1bdf2ae..e202d95 100644
--- a/src/oaipmh_scythe/scythe.py
+++ b/src/oaipmh_scythe/scythe.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/src/oaipmh_scythe/utils.py b/src/oaipmh_scythe/utils.py
index f3ecd30..e41c25b 100644
--- a/src/oaipmh_scythe/utils.py
+++ b/src/oaipmh_scythe/utils.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 69cac43..c365a19 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
 from __future__ import annotations
 
 import pytest
diff --git a/tests/integration/test_harvesting.py b/tests/integration/test_harvesting.py
index 6622e7a..b636ba1 100644
--- a/tests/integration/test_harvesting.py
+++ b/tests/integration/test_harvesting.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/tests/unit/test_client.py b/tests/unit/test_client.py
index fbbd7ec..431e59d 100644
--- a/tests/unit/test_client.py
+++ b/tests/unit/test_client.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
diff --git a/tests/unit/test_iterator.py b/tests/unit/test_iterator.py
index b442d16..bfa109a 100644
--- a/tests/unit/test_iterator.py
+++ b/tests/unit/test_iterator.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
 from __future__ import annotations
 
 import pytest
diff --git a/tests/unit/test_models.py b/tests/unit/test_models.py
index 07c5dc5..b780fbb 100644
--- a/tests/unit/test_models.py
+++ b/tests/unit/test_models.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
 import pytest
 from lxml import etree
 
diff --git a/tests/unit/test_response.py b/tests/unit/test_response.py
index a904f4c..a1b807e 100644
--- a/tests/unit/test_response.py
+++ b/tests/unit/test_response.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
 from __future__ import annotations
 
 from typing import TYPE_CHECKING
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index b348269..791ca47 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2015 Mathias Loesch
+# SPDX-FileCopyrightText: 2023 Heinz-Alexander Fuetterer
 #
 # SPDX-License-Identifier: BSD-3-Clause