diff --git a/src/Models/Game.php b/src/Models/Game.php
index 0a2c193..ca76460 100644
--- a/src/Models/Game.php
+++ b/src/Models/Game.php
@@ -11,7 +11,7 @@ namespace JeroenED\Libpairtwo\Models;
 use JeroenED\Libpairtwo\Enums\Gameresult;
 use JeroenED\Libpairtwo\Pairing;
 
-class Game
+abstract class Game
 {
     /** @var Pairing */
     private $white;
diff --git a/src/Models/Pairing.php b/src/Models/Pairing.php
index 4ec3138..8fc31a4 100644
--- a/src/Models/Pairing.php
+++ b/src/Models/Pairing.php
@@ -12,7 +12,7 @@ use JeroenED\Libpairtwo\Enums\Color;
 use JeroenED\Libpairtwo\Enums\Result;
 use JeroenED\Libpairtwo\Player;
 
-class Pairing
+abstract class Pairing
 {
     /** @var Player */
     private $Player;
diff --git a/src/Models/Player.php b/src/Models/Player.php
index 995cc29..eaa396d 100644
--- a/src/Models/Player.php
+++ b/src/Models/Player.php
@@ -13,7 +13,7 @@ use JeroenED\Libpairtwo\Enums\Gender;
 use JeroenED\Libpairtwo\Pairing;
 use DateTime;
 
-class Player
+abstract class Player
 {
     /** @var string */
     private $Name;
diff --git a/src/Models/Round.php b/src/Models/Round.php
index 5069c21..33bfde7 100644
--- a/src/Models/Round.php
+++ b/src/Models/Round.php
@@ -12,7 +12,7 @@ use DateTime;
 use JeroenED\Libpairtwo\Game;
 use JeroenED\Libpairtwo\Pairing;
 
-class Round
+abstract class Round
 {
     /** @var DateTime */
     private $date;
diff --git a/src/Models/Tournament.php b/src/Models/Tournament.php
index 6af6246..63467d3 100644
--- a/src/Models/Tournament.php
+++ b/src/Models/Tournament.php
@@ -35,7 +35,7 @@ use DateTime;
  *
  * @author Jeroen De Meerleer <schaak@jeroened.be>
  */
-class Tournament
+abstract class Tournament
 {
     /** @var string */
     private $Name;
diff --git a/src/Readers/Models/Pairtwo6.php b/src/Readers/Models/Pairtwo6.php
index 373ab8c..305f9e0 100644
--- a/src/Readers/Models/Pairtwo6.php
+++ b/src/Readers/Models/Pairtwo6.php
@@ -4,7 +4,7 @@ namespace JeroenED\Libpairtwo\Readers\Models;
 
 use JeroenED\Libpairtwo\Tournament;
 
-class Pairtwo6
+abstract class Pairtwo6
 {
     /** @var string */
     private $Release;