Book</A
></H1
><P
>   The documentation sources are written in
   <I
CLASS="FIRSTTERM"
>DocBook</I
>, which is a markup language
   superficially similar to <ACRONYM
CLASS="ACRONYM"
>HTML</ACRONYM
>.  Both of these
   languages are applications of the <I
CLASS="FIRSTTERM"
>Standard Generalized
   Markup Language</I
>, <ACRONYM
CLASS="ACRONYM"
>SGML</ACRONYM
>, which is
   essentially a language for describing other languages.  In what
   follows, the terms DocBook and <ACRONYM
CLASS="ACRONYM"
>SGML</ACRONYM