diff --git a/docProps.go b/docProps.go
index 41ea18e..fe6f214 100644
--- a/docProps.go
+++ b/docProps.go
@@ -204,7 +204,12 @@ func (f *File) SetDocProps(docProperties *DocProperties) (err error) {
 		Category:       core.Category,
 		Version:        core.Version,
 	}, nil
-	newProps.Created.Text, newProps.Created.Type, newProps.Modified.Text, newProps.Modified.Type = core.Created.Text, core.Created.Type, core.Modified.Text, core.Modified.Type
+	if core.Created != nil {
+		newProps.Created = &xlsxDcTerms{Type: core.Created.Type, Text: core.Created.Text}
+	}
+	if core.Modified != nil {
+		newProps.Modified = &xlsxDcTerms{Type: core.Modified.Type, Text: core.Modified.Text}
+	}
 	fields = []string{
 		"Category", "ContentStatus", "Creator", "Description", "Identifier", "Keywords",
 		"LastModifiedBy", "Revision", "Subject", "Title", "Language", "Version",
@@ -216,10 +221,10 @@ func (f *File) SetDocProps(docProperties *DocProperties) (err error) {
 		}
 	}
 	if docProperties.Created != "" {
-		newProps.Created.Text = docProperties.Created
+		newProps.Created = &xlsxDcTerms{Type: "dcterms:W3CDTF", Text: docProperties.Created}
 	}
 	if docProperties.Modified != "" {
-		newProps.Modified.Text = docProperties.Modified
+		newProps.Modified = &xlsxDcTerms{Type: "dcterms:W3CDTF", Text: docProperties.Modified}
 	}
 	output, err = xml.Marshal(newProps)
 	f.saveFileList(defaultXMLPathDocPropsCore, output)
@@ -239,19 +244,22 @@ func (f *File) GetDocProps() (ret *DocProperties, err error) {
 	ret, err = &DocProperties{
 		Category:       core.Category,
 		ContentStatus:  core.ContentStatus,
-		Created:        core.Created.Text,
 		Creator:        core.Creator,
 		Description:    core.Description,
 		Identifier:     core.Identifier,
 		Keywords:       core.Keywords,
 		LastModifiedBy: core.LastModifiedBy,
-		Modified:       core.Modified.Text,
 		Revision:       core.Revision,
 		Subject:        core.Subject,
 		Title:          core.Title,
 		Language:       core.Language,
 		Version:        core.Version,
 	}, nil
-
+	if core.Created != nil {
+		ret.Created = core.Created.Text
+	}
+	if core.Modified != nil {
+		ret.Modified = core.Modified.Text
+	}
 	return
 }
diff --git a/sheetview.go b/sheetview.go
index bf8f023..99f0634 100644
--- a/sheetview.go
+++ b/sheetview.go
@@ -163,6 +163,11 @@ func (f *File) getSheetView(sheet string, viewIndex int) (*xlsxSheetView, error)
 	if err != nil {
 		return nil, err
 	}
+	if ws.SheetViews == nil {
+		ws.SheetViews = &xlsxSheetViews{
+			SheetView: []xlsxSheetView{{WorkbookViewID: 0}},
+		}
+	}
 	if viewIndex < 0 {
 		if viewIndex < -len(ws.SheetViews.SheetView) {
 			return nil, fmt.Errorf("view index %d out of range", viewIndex)
diff --git a/sheetview_test.go b/sheetview_test.go
index 2bba8f9..65c4f51 100644
--- a/sheetview_test.go
+++ b/sheetview_test.go
@@ -210,4 +210,9 @@ func TestSheetViewOptionsErrors(t *testing.T) {
 	assert.NoError(t, f.SetSheetViewOptions(sheet, -1))
 	assert.Error(t, f.SetSheetViewOptions(sheet, 1))
 	assert.Error(t, f.SetSheetViewOptions(sheet, -2))
+
+	ws, ok := f.Sheet.Load("xl/worksheets/sheet1.xml")
+	assert.True(t, ok)
+	ws.(*xlsxWorksheet).SheetViews = nil
+	assert.NoError(t, f.GetSheetViewOptions(sheet, 0))
 }
diff --git a/xmlCore.go b/xmlCore.go
index 22ae6bc..1849131 100644
--- a/xmlCore.go
+++ b/xmlCore.go
@@ -31,61 +31,61 @@ type DocProperties struct {
 	Version        string
 }
 
+// decodeDcTerms directly maps the DCMI metadata terms for the coreProperties.
+type decodeDcTerms struct {
+	Text string `xml:",chardata"`
+	Type string `xml:"http://www.w3.org/2001/XMLSchema-instance type,attr"`
+}
+
 // decodeCoreProperties directly maps the root element for a part of this
 // content type shall coreProperties. In order to solve the problem that the
 // label structure is changed after serialization and deserialization, two
 // different structures are defined. decodeCoreProperties just for
 // deserialization.
 type decodeCoreProperties struct {
-	XMLName        xml.Name `xml:"http://schemas.openxmlformats.org/package/2006/metadata/core-properties coreProperties"`
-	Title          string   `xml:"http://purl.org/dc/elements/1.1/ title,omitempty"`
-	Subject        string   `xml:"http://purl.org/dc/elements/1.1/ subject,omitempty"`
-	Creator        string   `xml:"http://purl.org/dc/elements/1.1/ creator"`
-	Keywords       string   `xml:"keywords,omitempty"`
-	Description    string   `xml:"http://purl.org/dc/elements/1.1/ description,omitempty"`
-	LastModifiedBy string   `xml:"lastModifiedBy"`
-	Language       string   `xml:"http://purl.org/dc/elements/1.1/ language,omitempty"`
-	Identifier     string   `xml:"http://purl.org/dc/elements/1.1/ identifier,omitempty"`
-	Revision       string   `xml:"revision,omitempty"`
-	Created        struct {
-		Text string `xml:",chardata"`
-		Type string `xml:"http://www.w3.org/2001/XMLSchema-instance type,attr"`
-	} `xml:"http://purl.org/dc/terms/ created"`
-	Modified struct {
-		Text string `xml:",chardata"`
-		Type string `xml:"http://www.w3.org/2001/XMLSchema-instance type,attr"`
-	} `xml:"http://purl.org/dc/terms/ modified"`
-	ContentStatus string `xml:"contentStatus,omitempty"`
-	Category      string `xml:"category,omitempty"`
-	Version       string `xml:"version,omitempty"`
+	XMLName        xml.Name       `xml:"http://schemas.openxmlformats.org/package/2006/metadata/core-properties coreProperties"`
+	Title          string         `xml:"http://purl.org/dc/elements/1.1/ title,omitempty"`
+	Subject        string         `xml:"http://purl.org/dc/elements/1.1/ subject,omitempty"`
+	Creator        string         `xml:"http://purl.org/dc/elements/1.1/ creator"`
+	Keywords       string         `xml:"keywords,omitempty"`
+	Description    string         `xml:"http://purl.org/dc/elements/1.1/ description,omitempty"`
+	LastModifiedBy string         `xml:"lastModifiedBy"`
+	Language       string         `xml:"http://purl.org/dc/elements/1.1/ language,omitempty"`
+	Identifier     string         `xml:"http://purl.org/dc/elements/1.1/ identifier,omitempty"`
+	Revision       string         `xml:"revision,omitempty"`
+	Created        *decodeDcTerms `xml:"http://purl.org/dc/terms/ created"`
+	Modified       *decodeDcTerms `xml:"http://purl.org/dc/terms/ modified"`
+	ContentStatus  string         `xml:"contentStatus,omitempty"`
+	Category       string         `xml:"category,omitempty"`
+	Version        string         `xml:"version,omitempty"`
+}
+
+// xlsxDcTerms directly maps the DCMI metadata terms for the coreProperties.
+type xlsxDcTerms struct {
+	Text string `xml:",chardata"`
+	Type string `xml:"xsi:type,attr"`
 }
 
 // xlsxCoreProperties directly maps the root element for a part of this
 // content type shall coreProperties.
 type xlsxCoreProperties struct {
-	XMLName        xml.Name `xml:"http://schemas.openxmlformats.org/package/2006/metadata/core-properties coreProperties"`
-	Dc             string   `xml:"xmlns:dc,attr"`
-	Dcterms        string   `xml:"xmlns:dcterms,attr"`
-	Dcmitype       string   `xml:"xmlns:dcmitype,attr"`
-	XSI            string   `xml:"xmlns:xsi,attr"`
-	Title          string   `xml:"dc:title,omitempty"`
-	Subject        string   `xml:"dc:subject,omitempty"`
-	Creator        string   `xml:"dc:creator"`
-	Keywords       string   `xml:"keywords,omitempty"`
-	Description    string   `xml:"dc:description,omitempty"`
-	LastModifiedBy string   `xml:"lastModifiedBy"`
-	Language       string   `xml:"dc:language,omitempty"`
-	Identifier     string   `xml:"dc:identifier,omitempty"`
-	Revision       string   `xml:"revision,omitempty"`
-	Created        struct {
-		Text string `xml:",chardata"`
-		Type string `xml:"xsi:type,attr"`
-	} `xml:"dcterms:created"`
-	Modified struct {
-		Text string `xml:",chardata"`
-		Type string `xml:"xsi:type,attr"`
-	} `xml:"dcterms:modified"`
-	ContentStatus string `xml:"contentStatus,omitempty"`
-	Category      string `xml:"category,omitempty"`
-	Version       string `xml:"version,omitempty"`
+	XMLName        xml.Name     `xml:"http://schemas.openxmlformats.org/package/2006/metadata/core-properties coreProperties"`
+	Dc             string       `xml:"xmlns:dc,attr"`
+	Dcterms        string       `xml:"xmlns:dcterms,attr"`
+	Dcmitype       string       `xml:"xmlns:dcmitype,attr"`
+	XSI            string       `xml:"xmlns:xsi,attr"`
+	Title          string       `xml:"dc:title,omitempty"`
+	Subject        string       `xml:"dc:subject,omitempty"`
+	Creator        string       `xml:"dc:creator"`
+	Keywords       string       `xml:"keywords,omitempty"`
+	Description    string       `xml:"dc:description,omitempty"`
+	LastModifiedBy string       `xml:"lastModifiedBy"`
+	Language       string       `xml:"dc:language,omitempty"`
+	Identifier     string       `xml:"dc:identifier,omitempty"`
+	Revision       string       `xml:"revision,omitempty"`
+	Created        *xlsxDcTerms `xml:"dcterms:created"`
+	Modified       *xlsxDcTerms `xml:"dcterms:modified"`
+	ContentStatus  string       `xml:"contentStatus,omitempty"`
+	Category       string       `xml:"category,omitempty"`
+	Version        string       `xml:"version,omitempty"`
 }