diff --git a/Models/Machine.php b/Models/Machine.php
index 0c2d6e1..2287a0f 100644
--- a/Models/Machine.php
+++ b/Models/Machine.php
@@ -38,6 +38,11 @@ class Machine
 
     public int $unit = 0;
 
+    /**
+     * Constructor.
+     *
+     * @since 1.0.0
+     */
     public function __construct()
     {
         $this->equipment = new NullEquipment();
diff --git a/Models/Production.php b/Models/Production.php
index f068bed..d773106 100644
--- a/Models/Production.php
+++ b/Models/Production.php
@@ -46,6 +46,11 @@ class Production
 
     public Item $item;
 
+    /**
+     * Constructor.
+     *
+     * @since 1.0.0
+     */
     public function __construct()
     {
         $this->createdAt = new \DateTimeImmutable('now');