1 files changed, 13 insertions, 3 deletions

diff --git a/cell.go b/cell.go
index 5ec5976..aa4067f 100644
--- a/cell.go
+++ b/cell.go
@@ -1,3 +1,12 @@
+// 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 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.
+
 package excelize
 
 import (
@@ -235,12 +244,13 @@ func (f *File) GetCellFormula(sheet, axis string) string {
 		if xlsx.SheetData.Row[k].R == row {
 			for i := range xlsx.SheetData.Row[k].C {
 				if axis == xlsx.SheetData.Row[k].C[i].R {
+					if xlsx.SheetData.Row[k].C[i].F == nil {
+						continue
+					}
 					if xlsx.SheetData.Row[k].C[i].F.T == STCellFormulaTypeShared {
 						return getSharedForumula(xlsx, xlsx.SheetData.Row[k].C[i].F.Si)
 					}
-					if xlsx.SheetData.Row[k].C[i].F != nil {
-						return xlsx.SheetData.Row[k].C[i].F.Content
-					}
+					return xlsx.SheetData.Row[k].C[i].F.Content
 				}
 			}
 		}