diff --git a/src/Executor/ExecutionResult.php b/src/Executor/ExecutionResult.php
index 043ddc8..dbc3591 100644
--- a/src/Executor/ExecutionResult.php
+++ b/src/Executor/ExecutionResult.php
@@ -78,7 +78,7 @@ class ExecutionResult implements \JsonSerializable
      * );
      *
      * @api
-     * @return $this
+     * @return self
      */
     public function setErrorFormatter(callable $errorFormatter)
     {
@@ -98,7 +98,7 @@ class ExecutionResult implements \JsonSerializable
      * }
      *
      * @api
-     * @return $this
+     * @return self
      */
     public function setErrorsHandler(callable $handler)
     {
diff --git a/src/Language/AST/Node.php b/src/Language/AST/Node.php
index e12deec..4645c4f 100644
--- a/src/Language/AST/Node.php
+++ b/src/Language/AST/Node.php
@@ -48,7 +48,7 @@ abstract class Node
     }
 
     /**
-     * @return $this
+     * @return self
      */
     public function cloneDeep()
     {
diff --git a/src/Language/Lexer.php b/src/Language/Lexer.php
index 924f8e0..e39d933 100644
--- a/src/Language/Lexer.php
+++ b/src/Language/Lexer.php
@@ -690,7 +690,7 @@ class Lexer
      *
      * @param $positionOffset
      * @param $byteStreamOffset
-     * @return $this
+     * @return self
      */
     private function moveStringCursor($positionOffset, $byteStreamOffset)
     {