Here are the docs for nmap.  You would be better
off checking the website at http:https://www.insecure.org/nmap
for the latest information.  Also if the man page is installed
correctly you should be able to 'man nmap'.  The man page is more 
up-to-date than the article.  See nmap-manpage.html for an html version
of it.

-Fyodor