Project Xanadu - The original hypertext project. Includes a history of the project and gives credit to the early developers of markup languages.
XML Activity Statement - An executive overview of W3C's current and historical work on the Extensible Markup Language (XML).
YAML Ain't Markup Language (YAML) - A straightforward machine parsable data serialization format designed for human readability and interaction with scripting languages such as Perl and Python.
