Entities: DocBook versus XHTML

[Warren Block]

The FDP Primer, which I have been bludgeoning lately, has no section 
that really tells the basic FreeBSD-specific entities available, either 
in XHTML or DocBook or both.

The XHTML section does not show the correct way to refer to a Handbook 
chapter or an article.

&os; is only used a couple of times in the entire FDP Primer, and those 
are new, and I added them!

So please, let's collect a list of the most basic entities, and add it. 
I'm also curious to know why some but not all of the DocBook entities 
can be used in XHTML.


FreeBSD DocBook Entities
   Entity Name		Expands To
   ------------------------------------
   &os;			FreeBSD
   &os.current;		FreeBSD-CURRENT
   &os.stable;		FreeBSD-STABLE
   &url.books.handbook;	../../../..

Effectively, that last one works out to 
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook


FreeBSD XHTML Entities
   Entity Name      Expands To
   ------------------------------------
   &base;           http://www.freebsd.org