diff --git a/src/AndX.php b/src/AndX.php
index 526b300..04330dc 100644
--- a/src/AndX.php
+++ b/src/AndX.php
@@ -10,12 +10,12 @@ class AndX extends CompositeSpecification
     /**
      * @var SpecificationInterface
      */
-    private $x;
+    protected $x;
 
     /**
      * @var SpecificationInterface
      */
-    private $y;
+    protected $y;
 
     /**
      * @param SpecificationInterface $x
diff --git a/src/Not.php b/src/Not.php
index e51f949..d7f79be 100644
--- a/src/Not.php
+++ b/src/Not.php
@@ -10,7 +10,7 @@ class Not extends CompositeSpecification
     /**
      * @var SpecificationInterface
      */
-    private $wrapped;
+    protected $wrapped;
 
     /**
      * @param SpecificationInterface $x
diff --git a/src/OrX.php b/src/OrX.php
index b592122..2e4e460 100644
--- a/src/OrX.php
+++ b/src/OrX.php
@@ -10,12 +10,12 @@ class OrX extends CompositeSpecification
     /**
      * @var SpecificationInterface
      */
-    private $x;
+    protected $x;
 
     /**
      * @var SpecificationInterface
      */
-    private $y;
+    protected $y;
 
     /**
      * @param SpecificationInterface $x