diff --git a/.github/workflows/ctest.yml b/.github/workflows/ctest.yml
index 2e5ffb75..6d58bd58 100644
--- a/.github/workflows/ctest.yml
+++ b/.github/workflows/ctest.yml
@@ -23,6 +23,9 @@ jobs:
           - os: ubuntu-latest
             cc: gcc-11
             cxx: g++-11
+          - os: ubuntu-latest
+            cc: gcc-13
+            cxx: g++-13
           - os: ubuntu-latest
             cc: clang
             cxx: clang++
diff --git a/include/juno/math/juno_math.h b/include/juno/math/juno_math.h
index 3d30a958..cc5c76fd 100644
--- a/include/juno/math/juno_math.h
+++ b/include/juno/math/juno_math.h
@@ -1,3 +1,24 @@
+/*
+    MIT License
+
+    Copyright (c) 2025 Robin A. Onsay
+
+    Permission is hereby granted, free of charge, to any person obtaining
+    a copy of this software and associated documentation files
+    (the "Software"), to deal in the Software without restriction,
+    including without limitation the rights to use, copy, modify, merge,
+    publish, distribute, sublicense, and/or sell copies of the Software,
+    and to permit persons to whom the Software is furnished to do so,
+    subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+*/
+
+/**
+    @file Juno Math offers various math types and inline math functions
+*/
+
 #ifndef JUNO_H
 #define JUNO_H
 
diff --git a/include/juno/math/juno_math_constants.h b/include/juno/math/juno_math_constants.h
index 3a34e31e..bb995d02 100644
--- a/include/juno/math/juno_math_constants.h
+++ b/include/juno/math/juno_math_constants.h
@@ -1,3 +1,20 @@
+/*
+    MIT License
+
+    Copyright (c) 2025 Robin A. Onsay
+
+    Permission is hereby granted, free of charge, to any person obtaining
+    a copy of this software and associated documentation files
+    (the "Software"), to deal in the Software without restriction,
+    including without limitation the rights to use, copy, modify, merge,
+    publish, distribute, sublicense, and/or sell copies of the Software,
+    and to permit persons to whom the Software is furnished to do so,
+    subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+*/
+
 #ifndef JUNO_CONST_H
 #define JUNO_CONST_H
 
diff --git a/include/juno/math/juno_math_types.h b/include/juno/math/juno_math_types.h
index b230a569..7a047ebc 100644
--- a/include/juno/math/juno_math_types.h
+++ b/include/juno/math/juno_math_types.h
@@ -1,3 +1,20 @@
+/*
+    MIT License
+
+    Copyright (c) 2025 Robin A. Onsay
+
+    Permission is hereby granted, free of charge, to any person obtaining
+    a copy of this software and associated documentation files
+    (the "Software"), to deal in the Software without restriction,
+    including without limitation the rights to use, copy, modify, merge,
+    publish, distribute, sublicense, and/or sell copies of the Software,
+    and to permit persons to whom the Software is furnished to do so,
+    subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+*/
+
 #ifndef JUNO_TYPES_H
 #define JUNO_TYPES_H
 
diff --git a/include/juno/types.h b/include/juno/types.h
index 7fd6f898..a656abfa 100644
--- a/include/juno/types.h
+++ b/include/juno/types.h
@@ -1,3 +1,20 @@
+/*
+    MIT License
+
+    Copyright (c) 2025 Robin A. Onsay
+
+    Permission is hereby granted, free of charge, to any person obtaining
+    a copy of this software and associated documentation files
+    (the "Software"), to deal in the Software without restriction,
+    including without limitation the rights to use, copy, modify, merge,
+    publish, distribute, sublicense, and/or sell copies of the Software,
+    and to permit persons to whom the Software is furnished to do so,
+    subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+*/
+
 #ifndef JUNO_TYPES_H
 #define JUNO_TYPES_H
 #include "module.h"