Web standard for www or no www?

[admin]

I am having difficulties trying to express that we should make our domain accessable via <!-- m --><a class="postlink" href="http://domainname.com">http://domainname.com</a><!-- m --> as well as <!-- m --><a class="postlink" href="http://www.domainname.com">http://www.domainname.com</a><!-- m -->. I recall there being a website that wrote extensively on the pros of making sure your domain works both ways and how it should be SOP to do so. Does anyone have a link for that? I tried to search for it but came up with nothing.