Ever find a great site you used, bookmarked and then totally forgot about?? Well that's what happen with this one. It is a collaboratively created resource from MLS member librarians, where you will find freely available online sources that have been deemed reliable by fellow librarians. Also included are tools that may be helpful in your Reference work. It's is maintained by Anna Popp, of the Mass. Library System (MLS). Saw her in person and found her to be a great research instructor and source.
http://guides.masslibsystem.org/free_reference_resources