Reliable Vs. Nonreliable Sources

1. http://www.unrv.com/empire/gallic-sack-of-rome.php-RELIABLE-Story can be authenticated, writer known, sources listed in Bibliography at link: http://www.unrv.com/bibliography.php
This link also speaks about the writer.
2. http://www.ambafrance-uk.org/History-The-Gauls-and-the-Romans.html-RELIABLE-French Embassy Source, with links to the Embassy
3. http://www.megaessays.com/viewpaper/54837.html-NONRELIABLE-Trying to sell stuff.