  <spine toc="ncx">
    <itemref idref="<%= @config['bookname'] %>" linear="<%= @cover_linear %>"/>
<% if @config['mytoc'] %>
    <itemref idref="toc" />
<% end %>
<% @ncx_contents.each do |item| %>
    <itemref idref="<%= item.id %>"/>
<% end %>
  </spine>
