diff --git a/control.go b/control.go
index f6ac68d..f4d6a6b 100644
--- a/control.go
+++ b/control.go
@@ -1,4 +1,7 @@
-// preset.go
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// control.go
 package expr
 
 import "strings"
diff --git a/func-import.go b/func-import.go
index 1b4cd8c..d3d36b5 100644
--- a/func-import.go
+++ b/func-import.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // func-import.go
 package expr
 
diff --git a/func-math.go b/func-math.go
index b62a90b..fe6865c 100644
--- a/func-math.go
+++ b/func-math.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // funcs-math.go
 package expr
 
diff --git a/helpers.go b/helpers.go
index 48e1133..24bed45 100644
--- a/helpers.go
+++ b/helpers.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // helpers.go
 package expr
 
diff --git a/helpers_test.go b/helpers_test.go
index 4589013..3e80e05 100644
--- a/helpers_test.go
+++ b/helpers_test.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // helpers_test.go
 package expr
 
diff --git a/it-range.go b/it-range.go
index 8e2ec52..f67d3d1 100644
--- a/it-range.go
+++ b/it-range.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // it-range.go
 package expr
 
diff --git a/iterator.go b/iterator.go
index 5954515..c815f02 100644
--- a/iterator.go
+++ b/iterator.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // iterator.go
 package expr
 
diff --git a/simple-func-store.go b/simple-func-store.go
index 9079b9f..b75795a 100644
--- a/simple-func-store.go
+++ b/simple-func-store.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // simple-func-store.go
 package expr
 
diff --git a/simple-var-store.go b/simple-var-store.go
index 1d0ce1d..416eb17 100644
--- a/simple-var-store.go
+++ b/simple-var-store.go
@@ -1,3 +1,6 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
 // simple-var-store.go
 package expr