I'm not a copyright expert, but I think that simply publshing them on hubpages is proof they are yours. I have had my noval, Undercover, copyrighted, though I doubt anyone is going to try to steal a noval that may never get published, anyway. Its a lot of hard work getting anything out there, so most of our stuff is safe until it is already famous. Then the problem is with somebody else making money off of your effort, and not giving you proper credit, but in the case of most of us, we haven't even made any money off of our own stuff, so who'd want to steal it. To have an authentic copyright, you'd have to send it to :
Library of Congress
United States Copyright Office
101 Independence Avenue SE
Washington, DC 20559-6000
and I think they have an email address, as well.