I appreciate you brought up these links since some are outdated.
The old canonical site was < http://www.linuxdoc.org/ > but that
has now changed to < http://www.tldp.org/ > with language specific
sub sections in the way of, for instance < http://es.tldp.org/ > for
the Spanish language. More and more such sub sections are added,
currently there are about half a dozen.
Thus a link to < http://www.linuxdoc.org/HOWTO/ > brings up (at
least on my machine) the front page with a warning that you are
accessing the document using an outdated link, providing the new,
improved link to what you sought. A global search for linuxdoc.org
might therefore be useful, not just on your web sites but also
in the software.