diff --git a/file/exporter.go b/file/exporter.go
index 099ef87..96dfe37 100644
--- a/file/exporter.go
+++ b/file/exporter.go
@@ -1,3 +1,17 @@
+// Copyright (c) 2014, B3log
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package file
 
 import (
diff --git a/util/file.go b/util/file.go
index f2391c6..6330677 100644
--- a/util/file.go
+++ b/util/file.go
@@ -1,3 +1,17 @@
+// Copyright (c) 2014, B3log
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package util
 
 import (
diff --git a/util/go.go b/util/go.go
index f33e24f..7753565 100644
--- a/util/go.go
+++ b/util/go.go
@@ -1,3 +1,17 @@
+// Copyright (c) 2014, B3log
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package util
 
 import (
diff --git a/util/zip.go b/util/zip.go
index 41f5243..00383fd 100644
--- a/util/zip.go
+++ b/util/zip.go
@@ -1,3 +1,17 @@
+// Copyright (c) 2014, B3log
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package util
 
 import (