diff --git a/cmd/version.go b/cmd/version.go
index d91fce2..cdd8506 100644
--- a/cmd/version.go
+++ b/cmd/version.go
@@ -15,7 +15,7 @@ var versionCmd = &cobra.Command{
 	Short: "Print the version number of commonmeta",
 	Long:  `All software has versions. This is commonmeta's`,
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("Commonmeta v0.3.2 -- HEAD")
+		fmt.Println("Commonmeta v0.3.3 -- HEAD")
 	},
 }
 
diff --git a/crossrefxml/reader.go b/crossrefxml/reader.go
index 405d6b0..d6b801d 100644
--- a/crossrefxml/reader.go
+++ b/crossrefxml/reader.go
@@ -61,19 +61,16 @@ type DOIRecord struct {
 }
 
 type Crossref struct {
-	XMLName        xml.Name       `xml:"body"`
-	Xmlns          string         `xml:"xmlns,attr,omitempty"`
-	SchemaLocation string         `xml:"schemaLocation,attr,omitempty"`
-	Version        string         `xml:"version,attr,omitempty"`
-	Book           *Book          `xml:"book,omitempty"`
-	Conference     *Conference    `xml:"conference,omitempty"`
-	Database       *Database      `xml:"database,omitempty"`
-	Dissertation   *Dissertation  `xml:"dissertation,omitempty"`
-	Journal        *Journal       `xml:"journal,omitempty"`
-	PeerReview     *PeerReview    `xml:"peer_review,omitempty"`
-	PostedContent  *PostedContent `xml:"posted_content,omitempty"`
-	SAComponent    *SAComponent   `xml:"sa_component,omitempty"`
-	Standard       *Standard      `xml:"standard,omitempty"`
+	XMLName       xml.Name         `xml:"body"`
+	Book          []*Book          `xml:"book,omitempty"`
+	Conference    []*Conference    `xml:"conference,omitempty"`
+	Database      []*Database      `xml:"database,omitempty"`
+	Dissertation  []*Dissertation  `xml:"dissertation,omitempty"`
+	Journal       []*Journal       `xml:"journal,omitempty"`
+	PeerReview    []*PeerReview    `xml:"peer_review,omitempty"`
+	PostedContent []*PostedContent `xml:"posted_content,omitempty"`
+	SAComponent   []*SAComponent   `xml:"sa_component,omitempty"`
+	Standard      []*Standard      `xml:"standard,omitempty"`
 }
 
 type Abstract struct {
@@ -768,127 +765,138 @@ func Read(content Content) (commonmeta.Data, error) {
 	// fetch metadata depending on Crossref type (using the commonmeta vocabulary)
 	switch data.Type {
 	case "Article": // posted-content
-		abstract = meta.PostedContent.Abstract
+		postedContent := meta.PostedContent[0]
+		abstract = postedContent.Abstract
 		// archiveLocations not supported
-		citationList = meta.PostedContent.CitationList
-		contributors = meta.PostedContent.Contributors
-		doiData = meta.PostedContent.DOIData
-		itemNumber = meta.PostedContent.ItemNumber
-		language = meta.PostedContent.Language
+		citationList = postedContent.CitationList
+		contributors = postedContent.Contributors
+		doiData = postedContent.DOIData
+		itemNumber = postedContent.ItemNumber
+		language = postedContent.Language
 		// pages not supported
-		program = meta.PostedContent.Program
+		program = postedContent.Program
 		// use posted date as publication date
 		publicationDate = append(publicationDate, PublicationDate{
-			Year:  meta.PostedContent.PostedDate.Year,
-			Month: meta.PostedContent.PostedDate.Month,
-			Day:   meta.PostedContent.PostedDate.Day,
+			Year:  postedContent.PostedDate.Year,
+			Month: postedContent.PostedDate.Month,
+			Day:   postedContent.PostedDate.Day,
 		})
 		// use group title for subjects
-		subjects = append(subjects, meta.PostedContent.GroupTitle)
-		titles = meta.PostedContent.Titles
+		subjects = append(subjects, postedContent.GroupTitle)
+		titles = postedContent.Titles
 	case "Book":
-		abstract = meta.Book.BookMetadata.Abstract
-		contributors = meta.Book.BookMetadata.Contributors
-		citationList = meta.Book.ContentItem.CitationList
-		doiData = meta.Book.BookMetadata.DOIData
-		isbn = meta.Book.BookMetadata.ISBN
-		language = meta.Book.BookMetadata.Language
-		publicationDate = meta.Book.BookMetadata.PublicationDate
-		pages = meta.Book.ContentItem.Pages
-		titles = meta.Book.BookMetadata.Titles
+		book := meta.Book[0]
+		abstract = book.BookMetadata.Abstract
+		contributors = book.BookMetadata.Contributors
+		citationList = book.ContentItem.CitationList
+		doiData = book.BookMetadata.DOIData
+		isbn = book.BookMetadata.ISBN
+		language = book.BookMetadata.Language
+		publicationDate = book.BookMetadata.PublicationDate
+		pages = book.ContentItem.Pages
+		titles = book.BookMetadata.Titles
 	case "BookChapter":
-		abstract = meta.Book.BookMetadata.Abstract
-		citationList = meta.Book.ContentItem.CitationList
-		contributors = meta.Book.ContentItem.Contributors
-		doiData = meta.Book.BookMetadata.DOIData
-		isbn = meta.Book.BookMetadata.ISBN
-		language = meta.Book.BookMetadata.Language
-		publicationDate = meta.Book.ContentItem.PublicationDate
-		pages = meta.Book.ContentItem.Pages
-		titles = meta.Book.ContentItem.Titles
+		book := meta.Book[0]
+		abstract = book.BookMetadata.Abstract
+		citationList = book.ContentItem.CitationList
+		contributors = book.ContentItem.Contributors
+		doiData = book.BookMetadata.DOIData
+		isbn = book.BookMetadata.ISBN
+		language = book.BookMetadata.Language
+		publicationDate = book.ContentItem.PublicationDate
+		pages = book.ContentItem.Pages
+		titles = book.ContentItem.Titles
 	case "BookPart":
 	case "BookSection":
 	case "BookSeries":
 	case "BookSet":
 	case "BookTrack":
 	case "Component":
-		doiData = meta.SAComponent.ComponentList.Component[0].DOIData
+		component := meta.SAComponent[0]
+		doiData = component.ComponentList.Component[0].DOIData
 	case "Database":
 	case "Dataset":
-		containerTitle = meta.Database.DatabaseMetadata.Titles.Title
-		contributors = meta.Database.Dataset.Contributors
-		titles = meta.Database.Dataset.Titles
+		database := meta.Database[0]
+		containerTitle = database.DatabaseMetadata.Titles.Title
+		contributors = database.Dataset.Contributors
+		titles = database.Dataset.Titles
 		// use creation date as publication date
 		publicationDate = append(publicationDate, PublicationDate{
-			Year:  meta.Database.Dataset.DatabaseDate.CreationDate.Year,
-			Month: meta.Database.Dataset.DatabaseDate.CreationDate.Month,
-			Day:   meta.Database.Dataset.DatabaseDate.CreationDate.Day,
+			Year:  database.Dataset.DatabaseDate.CreationDate.Year,
+			Month: database.Dataset.DatabaseDate.CreationDate.Month,
+			Day:   database.Dataset.DatabaseDate.CreationDate.Day,
 		})
-		doiData = meta.Database.Dataset.DOIData
+		doiData = database.Dataset.DOIData
 	case "Dissertation":
+		dissertation := meta.Dissertation[0]
 		contributors = &Contributors{
-			PersonName: meta.Dissertation.PersonName,
+			PersonName: dissertation.PersonName,
 		}
-		doiData = meta.Dissertation.DOIData
+		doiData = dissertation.DOIData
 		// use approval date as publication date
 		publicationDate = append(publicationDate, PublicationDate{
-			Year:  meta.Dissertation.ApprovalDate.Year,
-			Month: meta.Dissertation.ApprovalDate.Month,
-			Day:   meta.Dissertation.ApprovalDate.Day,
+			Year:  dissertation.ApprovalDate.Year,
+			Month: dissertation.ApprovalDate.Month,
+			Day:   dissertation.ApprovalDate.Day,
 		})
-		titles = meta.Dissertation.Titles
+		titles = dissertation.Titles
 	case "Entry":
 	case "Grant":
 	case "Journal":
-		containerTitle = meta.Journal.JournalMetadata.FullTitle
-		language = meta.Journal.JournalMetadata.Language
-		doiData = meta.Journal.JournalMetadata.DOIData
+		journal := meta.Journal[0]
+		containerTitle = journal.JournalMetadata.FullTitle
+		language = journal.JournalMetadata.Language
+		doiData = journal.JournalMetadata.DOIData
 	case "JournalArticle":
-		abstract = meta.Journal.JournalArticle.Abstract
-		archiveLocations = meta.Journal.JournalArticle.ArchiveLocations
-		citationList = meta.Journal.JournalArticle.CitationList
-		containerTitle = meta.Journal.JournalMetadata.FullTitle
-		contributors = meta.Journal.JournalArticle.Contributors
-		customMetadata = meta.Journal.JournalArticle.Crossmark.CustomMetadata
-		doiData = meta.Journal.JournalArticle.DOIData
-		issn = meta.Journal.JournalMetadata.ISSN
-		issue = meta.Journal.JournalIssue.Issue
-		itemNumber = meta.Journal.JournalArticle.PublisherItem.ItemNumber
-		language = meta.Journal.JournalMetadata.Language
-		pages = meta.Journal.JournalArticle.Pages
-		program = append(program, meta.Journal.JournalArticle.Program...)
-		publicationDate = meta.Journal.JournalArticle.PublicationDate
-		titles = meta.Journal.JournalArticle.Titles
-		volume = meta.Journal.JournalIssue.JournalVolume.Volume
+		journal := meta.Journal[0]
+		abstract = journal.JournalArticle.Abstract
+		archiveLocations = journal.JournalArticle.ArchiveLocations
+		citationList = journal.JournalArticle.CitationList
+		containerTitle = journal.JournalMetadata.FullTitle
+		contributors = journal.JournalArticle.Contributors
+		customMetadata = journal.JournalArticle.Crossmark.CustomMetadata
+		doiData = journal.JournalArticle.DOIData
+		issn = journal.JournalMetadata.ISSN
+		issue = journal.JournalIssue.Issue
+		itemNumber = journal.JournalArticle.PublisherItem.ItemNumber
+		language = journal.JournalMetadata.Language
+		pages = journal.JournalArticle.Pages
+		program = append(program, journal.JournalArticle.Program...)
+		publicationDate = journal.JournalArticle.PublicationDate
+		titles = journal.JournalArticle.Titles
+		volume = journal.JournalIssue.JournalVolume.Volume
 	case "JournalIssue":
-		containerTitle = meta.Journal.JournalMetadata.FullTitle
-		doiData = meta.Journal.JournalIssue.DOIData
-		issn = meta.Journal.JournalMetadata.ISSN
-		language = meta.Journal.JournalMetadata.Language
+		journal := meta.Journal[0]
+		containerTitle = journal.JournalMetadata.FullTitle
+		doiData = journal.JournalIssue.DOIData
+		issn = journal.JournalMetadata.ISSN
+		language = journal.JournalMetadata.Language
 	case "JournalVolume":
 	case "Other":
 	case "PeerReview":
-		contributors = meta.PeerReview.Contributors
-		titles = meta.PeerReview.Titles
-		program = meta.PeerReview.Program
+		peerReview := meta.PeerReview[0]
+		contributors = peerReview.Contributors
+		titles = peerReview.Titles
+		program = peerReview.Program
 		// use review date as publication date
 		publicationDate = append(publicationDate, PublicationDate{
-			Year:  meta.PeerReview.ReviewDate.Year,
-			Month: meta.PeerReview.ReviewDate.Month,
-			Day:   meta.PeerReview.ReviewDate.Day,
+			Year:  peerReview.ReviewDate.Year,
+			Month: peerReview.ReviewDate.Month,
+			Day:   peerReview.ReviewDate.Day,
 		})
-		doiData = meta.PeerReview.DOIData
+		doiData = peerReview.DOIData
 	case "Proceedings":
 	case "ProceedingsArticle":
-		citationList = meta.Conference.ConferencePaper.CitationList
-		containerTitle = meta.Conference.EventMetadata.ConferenceName
-		contributors = meta.Conference.ConferencePaper.Contributors
-		doiData = meta.Conference.ConferencePaper.DOIData
-		isbn = meta.Conference.ProceedingsMetadata.ISBN
-		program = meta.Conference.ConferencePaper.Crossmark.CustomMetadata.Program
-		pages = meta.Conference.ConferencePaper.Pages
-		publicationDate = meta.Conference.ConferencePaper.PublicationDate
-		titles = meta.Conference.ConferencePaper.Titles
+		conference := meta.Conference[0]
+		citationList = conference.ConferencePaper.CitationList
+		containerTitle = conference.EventMetadata.ConferenceName
+		contributors = conference.ConferencePaper.Contributors
+		doiData = conference.ConferencePaper.DOIData
+		isbn = conference.ProceedingsMetadata.ISBN
+		program = conference.ConferencePaper.Crossmark.CustomMetadata.Program
+		pages = conference.ConferencePaper.Pages
+		publicationDate = conference.ConferencePaper.PublicationDate
+		titles = conference.ConferencePaper.Titles
 	case "ProceedingsSeries":
 	case "ReferenceBook":
 	case "Report":
@@ -1398,12 +1406,12 @@ func GetFundingReferences(fundref Program) ([]commonmeta.FundingReference, error
 func (c Content) Type() string {
 	switch c.Query.DOI.Type {
 	case "book_title":
-		if c.Query.DOIRecord.Crossref.Book.BookSetMetadata.SetMetadata.DOIData.DOI != "" {
+		if c.Query.DOIRecord.Crossref.Book[0].BookSetMetadata.SetMetadata.DOIData.DOI != "" {
 			return "BookSet"
 		}
 		return "Book"
 	case "book_content":
-		switch c.Query.DOIRecord.Crossref.Book.ContentItem.ComponentType {
+		switch c.Query.DOIRecord.Crossref.Book[0].ContentItem.ComponentType {
 		case "other":
 			return "Other"
 		case "part":
diff --git a/crossrefxml/reader_test.go b/crossrefxml/reader_test.go
index ba761dd..6acd6cb 100644
--- a/crossrefxml/reader_test.go
+++ b/crossrefxml/reader_test.go
@@ -35,9 +35,9 @@ func TestGet(t *testing.T) {
 		}
 		var resource string
 		if got.Query.DOI.Type == "journal-article" {
-			resource = got.Query.DOIRecord.Crossref.Journal.JournalArticle.DOIData.Resource
+			resource = got.Query.DOIRecord.Crossref.Journal[0].JournalArticle.DOIData.Resource
 		} else if got.Query.DOI.Type == "posted-content" {
-			resource = got.Query.DOIRecord.Crossref.PostedContent.DOIData.Resource
+			resource = got.Query.DOIRecord.Crossref.PostedContent[0].DOIData.Resource
 		}
 		if tc.want != resource {
 			t.Errorf("Get (%v): want %v, got %v, error %v",
diff --git a/crossrefxml/writer.go b/crossrefxml/writer.go
index a2d7208..cbf24ce 100644
--- a/crossrefxml/writer.go
+++ b/crossrefxml/writer.go
@@ -34,13 +34,13 @@ type Head struct {
 }
 
 type DOIBatch struct {
-	XMLName        xml.Name   `xml:"doi_batch"`
-	Xmlns          string     `xml:"xmlns,attr,omitempty"`
-	Version        string     `xml:"version,attr,omitempty"`
-	Xsi            string     `xml:"xsi,attr,omitempty"`
-	SchemaLocation string     `xml:"schemaLocation,attr,omitempty"`
-	Head           Head       `xml:"head"`
-	Body           []Crossref `xml:"body"`
+	XMLName        xml.Name `xml:"doi_batch"`
+	Xmlns          string   `xml:"xmlns,attr,omitempty"`
+	Version        string   `xml:"version,attr,omitempty"`
+	Xsi            string   `xml:"xsi,attr,omitempty"`
+	SchemaLocation string   `xml:"schemaLocation,attr,omitempty"`
+	Head           Head     `xml:"head"`
+	Body           Crossref `xml:"body"`
 }
 
 type Account struct {
@@ -327,7 +327,7 @@ func Convert(data commonmeta.Data) (Crossref, error) {
 				Day:       datePublished.Day,
 			}
 		}
-		c.PostedContent = &PostedContent{
+		c.PostedContent = append(c.PostedContent, &PostedContent{
 			Type:       "other",
 			Language:   data.Language,
 			GroupTitle: groupTitle,
@@ -341,9 +341,9 @@ func Convert(data commonmeta.Data) (Crossref, error) {
 			Program:      program,
 			DOIData:      doiData,
 			CitationList: &citationList,
-		}
+		})
 	case "JournalArticle":
-		c.Journal = &Journal{}
+		c.Journal = append(c.Journal, &Journal{})
 	}
 
 	return c, nil
@@ -356,8 +356,6 @@ func Write(data commonmeta.Data, account Account) ([]byte, []gojsonschema.Result
 		fmt.Println(err)
 	}
 
-	body := []Crossref{}
-	body = append(body, crossref)
 	depositor := Depositor{
 		DepositorName: account.Depositor,
 		Email:         account.Email,
@@ -373,7 +371,7 @@ func Write(data commonmeta.Data, account Account) ([]byte, []gojsonschema.Result
 		Xmlns:   "http://www.crossref.org/schema/5.3.1",
 		Version: "5.3.1",
 		Head:    head,
-		Body:    body,
+		Body:    crossref,
 	}
 
 	output, err := xml.MarshalIndent(doiBatch, "", "  ")
@@ -387,13 +385,23 @@ func Write(data commonmeta.Data, account Account) ([]byte, []gojsonschema.Result
 
 // WriteAll writes a list of commonmeta metadata.
 func WriteAll(list []commonmeta.Data, account Account) ([]byte, []gojsonschema.ResultError) {
-	var body []Crossref
+	var body Crossref
 	for _, data := range list {
 		crossref, err := Convert(data)
 		if err != nil {
 			fmt.Println(err)
 		}
-		body = append(body, crossref)
+		fmt.Print(crossref)
+		// workaround to handle the different content types
+		body.Book = append(body.Book, crossref.Book...)
+		body.Conference = append(body.Conference, crossref.Conference...)
+		body.Database = append(body.Database, crossref.Database...)
+		body.Dissertation = append(body.Dissertation, crossref.Dissertation...)
+		body.Journal = append(body.Journal, crossref.Journal...)
+		body.PeerReview = append(body.PeerReview, crossref.PeerReview...)
+		body.PostedContent = append(body.PostedContent, crossref.PostedContent...)
+		body.SAComponent = append(body.SAComponent, crossref.SAComponent...)
+		body.Standard = append(body.Standard, crossref.Standard...)
 	}
 	depositor := Depositor{
 		DepositorName: account.Depositor,