 them into a separate file and include it into all
documents you want to use them in, using the :rst:dir:`include` directive.  (Be
sure to give the include file a file name extension differing from that of other
source files, to avoid Sphinx finding it as a standalone document.)

Sphinx defines some default substitutions, see :ref:`default-substitutions`.


Comments
--------

Every explicit markup block which isn't a valid markup construct (like the
footnotes above) is regarded as a comment (:duref:`ref &lt