diff --git a/app/lib/expense.tsx b/app/lib/expense.tsx
index 2345d54..6964776 100644
--- a/app/lib/expense.tsx
+++ b/app/lib/expense.tsx
@@ -1,3 +1,5 @@
+/* Copyright (C) 2024 Manuel Bustillo*/
+
 import { Serializable } from "../api/abstract-api";
 import { Entity } from "./definitions";
 
diff --git a/app/lib/group.tsx b/app/lib/group.tsx
index cc2adc5..387e557 100644
--- a/app/lib/group.tsx
+++ b/app/lib/group.tsx
@@ -1,3 +1,5 @@
+/* Copyright (C) 2024 Manuel Bustillo*/
+
 import { Entity } from "./definitions";
 
 export type AttendanceSummary = {
diff --git a/app/lib/guest.tsx b/app/lib/guest.tsx
index 6b7abcd..0baddfe 100644
--- a/app/lib/guest.tsx
+++ b/app/lib/guest.tsx
@@ -1,3 +1,5 @@
+/* Copyright (C) 2024 Manuel Bustillo*/
+
 import { Serializable } from "../api/abstract-api";
 import { Entity } from "./definitions";