The document provides an overview of steps to mark up a bibliography text file into HTML, XML, and XHTML formats. The steps include:
1) Downloading the text file using FTP and marking it up as HTML.
2) Creating an XML file from the text by adding tags and validating that it is well-formed.
3) Defining a DTD to validate the XML file.
4) Converting the HTML file into XHTML and validating it against an external DTD.
5) Creating an XSL stylesheet to transform the XML into HTML for display on the web.