diff --git a/internal/doc.go b/internal/doc.go
new file mode 100644
index 0000000..03265e8
--- /dev/null
+++ b/internal/doc.go
@@ -0,0 +1,6 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package internal contains support packages for oauth2 package.
+package internal
diff --git a/internal/oauth2.go b/internal/oauth2.go
index e31541b..6978192 100644
--- a/internal/oauth2.go
+++ b/internal/oauth2.go
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package internal contains support packages for oauth2 package.
 package internal
 
 import (
diff --git a/internal/oauth2_test.go b/internal/oauth2_test.go
index 0aafc7f..07d51c4 100644
--- a/internal/oauth2_test.go
+++ b/internal/oauth2_test.go
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package internal contains support packages for oauth2 package.
 package internal
 
 import (
diff --git a/internal/token.go b/internal/token.go
index 53ec23c..cf959ea 100644
--- a/internal/token.go
+++ b/internal/token.go
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package internal contains support packages for oauth2 package.
 package internal
 
 import (
diff --git a/internal/token_test.go b/internal/token_test.go
index c19a462..df5eb26 100644
--- a/internal/token_test.go
+++ b/internal/token_test.go
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package internal contains support packages for oauth2 package.
 package internal
 
 import (
diff --git a/internal/transport.go b/internal/transport.go
index f1f173e..783bd98 100644
--- a/internal/transport.go
+++ b/internal/transport.go
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package internal contains support packages for oauth2 package.
 package internal
 
 import (