diff --git a/src/GeographicalSubdivision.php b/src/GeographicalSubdivision.php
index 949f923..ec4b4ac 100644
--- a/src/GeographicalSubdivision.php
+++ b/src/GeographicalSubdivision.php
@@ -4,10 +4,17 @@
 
 namespace MLocati\ComuniItaliani;
 
-final class GeographicalSubdivision extends TerritoryWithChildren
+final class GeographicalSubdivision implements TerritoryWithChildren
 {
+    private array $data;
+
     private ?array $regions = null;
 
+    public function __construct(array $data)
+    {
+        $this->data = $data;
+    }
+
     /**
      * {@inheritdoc}
      *
diff --git a/src/Municipality.php b/src/Municipality.php
index 00efd4d..183628f 100644
--- a/src/Municipality.php
+++ b/src/Municipality.php
@@ -4,13 +4,15 @@
 
 namespace MLocati\ComuniItaliani;
 
-final class Municipality extends Territory
+final class Municipality implements Territory
 {
+    private array $data;
+
     private Province $province;
 
     public function __construct(array $data, Province $province)
     {
-        parent::__construct($data);
+        $this->data = $data;
         $this->province = $province;
     }
 
diff --git a/src/Province.php b/src/Province.php
index beef931..c480e51 100644
--- a/src/Province.php
+++ b/src/Province.php
@@ -4,15 +4,17 @@
 
 namespace MLocati\ComuniItaliani;
 
-final class Province extends TerritoryWithChildren
+final class Province implements TerritoryWithChildren
 {
+    private array $data;
+
     private Region $region;
 
     private ?array $municipalities = null;
 
     public function __construct(array $data, Region $region)
     {
-        parent::__construct($data);
+        $this->data = $data;
         $this->region = $region;
     }
 
diff --git a/src/Region.php b/src/Region.php
index 54e7d96..6de85bc 100644
--- a/src/Region.php
+++ b/src/Region.php
@@ -4,15 +4,17 @@
 
 namespace MLocati\ComuniItaliani;
 
-final class Region extends TerritoryWithChildren
+final class Region implements TerritoryWithChildren
 {
+    private array $data;
+
     private GeographicalSubdivision $geographicalSubdivision;
 
     private ?array $provinces = null;
 
     public function __construct(array $data, GeographicalSubdivision $geographicalSubdivision)
     {
-        parent::__construct($data);
+        $this->data = $data;
         $this->geographicalSubdivision = $geographicalSubdivision;
     }
 
diff --git a/src/Territory.php b/src/Territory.php
index f4fa15e..3681975 100644
--- a/src/Territory.php
+++ b/src/Territory.php
@@ -4,23 +4,16 @@
 
 namespace MLocati\ComuniItaliani;
 
-abstract class Territory
+interface Territory
 {
-    protected array $data;
-
-    public function __construct(array $data)
-    {
-        $this->data = $data;
-    }
-
     /**
      * @return string|int
      */
-    abstract public function getID();
+    public function getID();
 
-    abstract public function getParent(): ?Territory;
+    public function getParent(): ?Territory;
 
-    abstract public function getName(): string;
+    public function getName(): string;
 
-    abstract public function __toString(): string;
+    public function __toString(): string;
 }
diff --git a/src/TerritoryWithChildren.php b/src/TerritoryWithChildren.php
index 05cee63..d481202 100644
--- a/src/TerritoryWithChildren.php
+++ b/src/TerritoryWithChildren.php
@@ -4,10 +4,10 @@
 
 namespace MLocati\ComuniItaliani;
 
-abstract class TerritoryWithChildren extends Territory
+interface TerritoryWithChildren extends Territory
 {
     /**
      * @return \MLocati\ComuniItaliani\Territory[]
      */
-    abstract public function getChildren(): array;
+    public function getChildren(): array;
 }