diff --git a/parso/pgen2/__init__.py b/parso/pgen2/__init__.py
index 1ddae5f..5e4cfc0 100644
--- a/parso/pgen2/__init__.py
+++ b/parso/pgen2/__init__.py
@@ -4,5 +4,5 @@
 # Modifications:
 # Copyright 2006 Google, Inc. All Rights Reserved.
 # Licensed to PSF under a Contributor Agreement.
-# Copyright 2014 David Halter. Integration into Jedi.
+# Copyright 2014 David Halter and Contributors
 # Modifications are dual-licensed: MIT and PSF.
diff --git a/parso/pgen2/grammar.py b/parso/pgen2/grammar.py
index 285e606..bb51530 100644
--- a/parso/pgen2/grammar.py
+++ b/parso/pgen2/grammar.py
@@ -2,7 +2,7 @@
 # Licensed to PSF under a Contributor Agreement.
 
 # Modifications:
-# Copyright 2014 David Halter. Integration into Jedi.
+# Copyright David Halter and Contributors
 # Modifications are dual-licensed: MIT and PSF.
 
 """This module defines the data structures used to represent a grammar.
diff --git a/parso/pgen2/parse.py b/parso/pgen2/parse.py
index a23db82..e2d9593 100644
--- a/parso/pgen2/parse.py
+++ b/parso/pgen2/parse.py
@@ -2,7 +2,7 @@
 # Licensed to PSF under a Contributor Agreement.
 
 # Modifications:
-# Copyright 2014-2018 David Halter.
+# Copyright David Halter and Contributors
 # Modifications are dual-licensed: MIT and PSF.
 
 """
diff --git a/parso/pgen2/pgen.py b/parso/pgen2/pgen.py
index 9a8fc55..00201e5 100644
--- a/parso/pgen2/pgen.py
+++ b/parso/pgen2/pgen.py
@@ -2,7 +2,7 @@
 # Licensed to PSF under a Contributor Agreement.
 
 # Modifications:
-# Copyright 2014-2018 David Halter.
+# Copyright David Halter and Contributors
 # Modifications are dual-licensed: MIT and PSF.
 
 from parso.pgen2.grammar import Grammar