title_body: how to create hypertext local to an EPUB document? Trying to explain the title: I am creating an EPUB document which is a programming course. In the document I want to refer to texts describing labs: these are not in the main flow of the main document: you can click if you want to read the labs (or not) and then get back to the main document.
  
  In the lab documents there are also links to solutions (you need to click and later come back)
  
  this means I want to have an hypertext tree in my epub with a main text with a normal flow and additions which are not part of the normal flow.
  How do I do that?
  thanks
  
  (note: EPUB is created using ASCIIDOC but I can write unix scripts massaging the files in the zip)
upvoted_answer: I don't really understand the question, but it is possible for an epub file to contain html files which do not appear in the main navigation document. They can be accessed indirectly through hyperlinks within the HTML document. 
  
  See the answer I gave for a different but related question here: https://ebooks.stackexchange.com/a/7211/417
  
  By the way, if that is your question,  I recommend ignoring the epub2 way to do it and just do it the epub3 way. A lot of reading systems (including the Kindle ones) are ignoring the toc.ncx document if you have a &lt;nav epub:type="toc"&gt; element.