code: def to_xml
        Nokogiri::XML::Builder.new(encoding: 'UTF-8') do |xml|
          xml.bibitem(id: id) do
            xml.fetched fetched
            title.each { |t| xml.title { t.to_xml xml } }
            link.each { |s| s.to_xml xml }
            docidentifier.each { |di| di.to_xml xml }
            dates.each { |d| d.to_xml xml, full_date: true }
            contributors.each do |c|
              xml.contributor do
                c.role.each { |r| r.to_xml xml }
                c.to_xml xml
              end
            end
            language.each { |l| xml.language l }
            script.each { |s| xml.script s }
            abstract.each { |a| xml.abstract { a.to_xml(xml) } }
            status.to_xml xml if status
            copyright.to_xml xml if copyright
            relations.each { |r| r.to_xml xml }
            series.each { |s| s.to_xml xml } if series
          end
        end.doc.root.to_xml
      end
docs: rubocop:disable Metrics/AbcSize, Metrics/MethodLength
   @return [String]