out names (``[#]_``).


Citations
---------

Standard reST citations (:duref:`ref &lt;citations&gt;`) are supported, with the
additional feature that they are "global", i.e. all citations can be referenced
from all files.  Use them like so::

   Lorem ipsum [Ref]_ dolor sit amet.

   .. [Ref] Book or article reference, URL or whatever.

Citation usage is similar to footnote usage, but with a label that is not
numeric or begins with ``#``.


Substitutions
-------------

reST supports "substitutions" (:duref: