diff --git a/cell.go b/cell.go
index 5ec5976eb8..e6755d6663 100644
--- a/cell.go
+++ b/cell.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/chart.go b/chart.go
index 8e1d7e9f9b..204768497b 100644
--- a/chart.go
+++ b/chart.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/col.go b/col.go
index e3870ee8b8..cddb09f45a 100644
--- a/col.go
+++ b/col.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/comment.go b/comment.go
index 8bf4fd31a5..32ed02f2fd 100644
--- a/comment.go
+++ b/comment.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/datavalidation.go b/datavalidation.go
index 010615c460..be3caabe92 100644
--- a/datavalidation.go
+++ b/datavalidation.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
@@ -128,7 +136,7 @@ func (dd *DataValidation) SetSqrefDropList(sqref string, isCurrentSheet bool) er
 	}
 
 	//isCurrentSheet = false   Cross-sheet sqref cell use extLst xml node  unrealized
-	return fmt.Errorf("Cross-sheet sqref cell  are not supported")
+	return fmt.Errorf("cross-sheet sqref cell are not supported")
 }
 
 // SetSqref provides function to set data validation range in drop list.
diff --git a/datavalidation_test.go b/datavalidation_test.go
index f3db81c6c0..8134b721a5 100644
--- a/datavalidation_test.go
+++ b/datavalidation_test.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/date.go b/date.go
index 72336610db..56d6ad7ae7 100644
--- a/date.go
+++ b/date.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/excelize.go b/excelize.go
index 0b530ab219..915955c8fb 100644
--- a/excelize.go
+++ b/excelize.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/file.go b/file.go
index a45fc28352..76ef98687a 100644
--- a/file.go
+++ b/file.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
@@ -43,7 +51,7 @@ func NewFile() *File {
 // Save provides a function to override the xlsx file with origin path.
 func (f *File) Save() error {
 	if f.Path == "" {
-		return fmt.Errorf("No path defined for file, consider File.WriteTo or File.Write")
+		return fmt.Errorf("no path defined for file, consider File.WriteTo or File.Write")
 	}
 	return f.SaveAs(f.Path)
 }
diff --git a/hsl.go b/hsl.go
index bd868b12a7..fd10b5dae8 100644
--- a/hsl.go
+++ b/hsl.go
@@ -1,33 +1,35 @@
-/*
-Copyright (c) 2012 Rodrigo Moraes. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-	 * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-	 * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-	 * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-*/
-
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright (c) 2012 Rodrigo Moraes. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// 	 * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// 	 * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// 	 * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 package excelize
 
 import (
diff --git a/lib.go b/lib.go
index 8013efa3fa..5be9b16213 100644
--- a/lib.go
+++ b/lib.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/picture.go b/picture.go
index 97e72a6645..decc37db4e 100644
--- a/picture.go
+++ b/picture.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
@@ -86,10 +94,10 @@ func (f *File) AddPicture(sheet, cell, picture, format string) error {
 	}
 	ext, ok := supportImageTypes[path.Ext(picture)]
 	if !ok {
-		return errors.New("Unsupported image extension")
+		return errors.New("unsupported image extension")
 	}
 	readFile, err := os.Open(picture)
-	if err!=nil{
+	if err != nil {
 		return err
 	}
 	defer readFile.Close()
diff --git a/rows.go b/rows.go
index 521a945424..8e1e0c3bb3 100644
--- a/rows.go
+++ b/rows.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/shape.go b/shape.go
index 8fbfbcd394..42aefcf99c 100644
--- a/shape.go
+++ b/shape.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
diff --git a/sheet.go b/sheet.go
index 011ecb8584..b5c3e6cb0d 100644
--- a/sheet.go
+++ b/sheet.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
@@ -371,7 +379,7 @@ func (f *File) SetSheetBackground(sheet, picture string) error {
 	}
 	ext, ok := supportImageTypes[path.Ext(picture)]
 	if !ok {
-		return errors.New("Unsupported image extension")
+		return errors.New("unsupported image extension")
 	}
 	pictureID := f.countMedia() + 1
 	rID := f.addSheetRelationships(sheet, SourceRelationshipImage, "../media/image"+strconv.Itoa(pictureID)+ext, "")
@@ -441,7 +449,7 @@ func (f *File) deleteSheetFromContentTypes(target string) {
 //
 func (f *File) CopySheet(from, to int) error {
 	if from < 1 || to < 1 || from == to || f.GetSheetName(from) == "" || f.GetSheetName(to) == "" {
-		return errors.New("Invalid worksheet index")
+		return errors.New("invalid worksheet index")
 	}
 	f.copySheet(from, to)
 	return nil
diff --git a/sheetpr.go b/sheetpr.go
index 1601ab138c..a010130a38 100644
--- a/sheetpr.go
+++ b/sheetpr.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 // SheetPrOption is an option of a view of a worksheet. See SetSheetPrOptions().
diff --git a/sheetview.go b/sheetview.go
index 679e915391..5e756ead27 100644
--- a/sheetview.go
+++ b/sheetview.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "fmt"
diff --git a/styles.go b/styles.go
index a288b3706f..80f347ecbd 100644
--- a/styles.go
+++ b/styles.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
@@ -798,35 +806,35 @@ var validType = map[string]string{
 
 // criteriaType defined the list of valid criteria types.
 var criteriaType = map[string]string{
-	"between":      "between",
-	"not between":  "notBetween",
-	"equal to":     "equal",
-	"=":            "equal",
-	"==":           "equal",
-	"not equal to": "notEqual",
-	"!=":           "notEqual",
-	"<>":           "notEqual",
-	"greater than": "greaterThan",
-	">":            "greaterThan",
-	"less than":    "lessThan",
-	"<":            "lessThan",
+	"between":                  "between",
+	"not between":              "notBetween",
+	"equal to":                 "equal",
+	"=":                        "equal",
+	"==":                       "equal",
+	"not equal to":             "notEqual",
+	"!=":                       "notEqual",
+	"<>":                       "notEqual",
+	"greater than":             "greaterThan",
+	">":                        "greaterThan",
+	"less than":                "lessThan",
+	"<":                        "lessThan",
 	"greater than or equal to": "greaterThanOrEqual",
-	">=": "greaterThanOrEqual",
-	"less than or equal to": "lessThanOrEqual",
-	"<=":             "lessThanOrEqual",
-	"containing":     "containsText",
-	"not containing": "notContains",
-	"begins with":    "beginsWith",
-	"ends with":      "endsWith",
-	"yesterday":      "yesterday",
-	"today":          "today",
-	"last 7 days":    "last7Days",
-	"last week":      "lastWeek",
-	"this week":      "thisWeek",
-	"continue week":  "continueWeek",
-	"last month":     "lastMonth",
-	"this month":     "thisMonth",
-	"continue month": "continueMonth",
+	">=":                       "greaterThanOrEqual",
+	"less than or equal to":    "lessThanOrEqual",
+	"<=":                       "lessThanOrEqual",
+	"containing":               "containsText",
+	"not containing":           "notContains",
+	"begins with":              "beginsWith",
+	"ends with":                "endsWith",
+	"yesterday":                "yesterday",
+	"today":                    "today",
+	"last 7 days":              "last7Days",
+	"last week":                "lastWeek",
+	"this week":                "thisWeek",
+	"continue week":            "continueWeek",
+	"last month":               "lastMonth",
+	"this month":               "thisMonth",
+	"continue month":           "continueMonth",
 }
 
 // formatToString provides a function to return original string by given
diff --git a/table.go b/table.go
index 643b156c87..fcc4d3c327 100644
--- a/table.go
+++ b/table.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import (
@@ -282,7 +290,7 @@ func (f *File) autoFilter(sheet, ref string, refRange, hxAxis int, formatSet *fo
 	col := TitleToNumber(formatSet.Column)
 	offset := col - hxAxis
 	if offset < 0 || offset > refRange {
-		return fmt.Errorf("Incorrect index of column '%s'", formatSet.Column)
+		return fmt.Errorf("incorrect index of column '%s'", formatSet.Column)
 	}
 	filter.FilterColumn = &xlsxFilterColumn{
 		ColID: offset,
@@ -290,7 +298,7 @@ func (f *File) autoFilter(sheet, ref string, refRange, hxAxis int, formatSet *fo
 	re := regexp.MustCompile(`"(?:[^"]|"")*"|\S+`)
 	token := re.FindAllString(formatSet.Expression, -1)
 	if len(token) != 3 && len(token) != 7 {
-		return fmt.Errorf("Incorrect number of tokens in criteria '%s'", formatSet.Expression)
+		return fmt.Errorf("incorrect number of tokens in criteria '%s'", formatSet.Expression)
 	}
 	expressions, tokens, err := f.parseFilterExpression(formatSet.Expression, token)
 	if err != nil {
@@ -415,7 +423,7 @@ func (f *File) parseFilterTokens(expression string, tokens []string) ([]int, str
 	operator, ok := operators[strings.ToLower(tokens[1])]
 	if !ok {
 		// Convert the operator from a number to a descriptive string.
-		return []int{}, "", fmt.Errorf("Unknown operator: %s", tokens[1])
+		return []int{}, "", fmt.Errorf("unknown operator: %s", tokens[1])
 	}
 	token := tokens[2]
 	// Special handling for Blanks/NonBlanks.
@@ -423,7 +431,7 @@ func (f *File) parseFilterTokens(expression string, tokens []string) ([]int, str
 	if re {
 		// Only allow Equals or NotEqual in this context.
 		if operator != 2 && operator != 5 {
-			return []int{operator}, token, fmt.Errorf("The operator '%s' in expression '%s' is not valid in relation to Blanks/NonBlanks'", tokens[1], expression)
+			return []int{operator}, token, fmt.Errorf("the operator '%s' in expression '%s' is not valid in relation to Blanks/NonBlanks'", tokens[1], expression)
 		}
 		token = strings.ToLower(token)
 		// The operator should always be 2 (=) to flag a "simple" equality in
diff --git a/templates.go b/templates.go
index ef6058cbc6..a619dfc286 100644
--- a/templates.go
+++ b/templates.go
@@ -1,6 +1,14 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize Authors. All rights reserved. Use of
+// this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+//
 // This file contains default templates for XML files we don't yet populated
 // based on content.
-
 package excelize
 
 // XMLHeader define an XML declaration can also contain a standalone declaration.
diff --git a/vmlDrawing.go b/vmlDrawing.go
index 307186a95e..f9323721c4 100644
--- a/vmlDrawing.go
+++ b/vmlDrawing.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlChart.go b/xmlChart.go
index a263334307..8a2cfd8018 100644
--- a/xmlChart.go
+++ b/xmlChart.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlComments.go b/xmlComments.go
index fadc9b3873..08d85c1cb0 100644
--- a/xmlComments.go
+++ b/xmlComments.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlContentTypes.go b/xmlContentTypes.go
index 121c6846bf..6c31bffa67 100644
--- a/xmlContentTypes.go
+++ b/xmlContentTypes.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlDecodeDrawing.go b/xmlDecodeDrawing.go
index fff6b9debf..c85c490d3d 100644
--- a/xmlDecodeDrawing.go
+++ b/xmlDecodeDrawing.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlDrawing.go b/xmlDrawing.go
index beb6bc94a4..ee30a4ddf1 100644
--- a/xmlDrawing.go
+++ b/xmlDrawing.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlSharedStrings.go b/xmlSharedStrings.go
index c8b54a013a..94959c65dc 100644
--- a/xmlSharedStrings.go
+++ b/xmlSharedStrings.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlStyles.go b/xmlStyles.go
index 05ff22bc4d..3024c1e2b3 100644
--- a/xmlStyles.go
+++ b/xmlStyles.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlTable.go b/xmlTable.go
index b238350267..53a5af432a 100644
--- a/xmlTable.go
+++ b/xmlTable.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlTheme.go b/xmlTheme.go
index d2ab343ceb..e72e53b98a 100644
--- a/xmlTheme.go
+++ b/xmlTheme.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlWorkbook.go b/xmlWorkbook.go
index 816d5a4617..d194bac46d 100644
--- a/xmlWorkbook.go
+++ b/xmlWorkbook.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"
diff --git a/xmlWorksheet.go b/xmlWorksheet.go
index 7cf4994e82..e298329d81 100644
--- a/xmlWorksheet.go
+++ b/xmlWorksheet.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize 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 excelize
 
 import "encoding/xml"