Encyclopedias, especially subject-specific enclyclopedias, and general reference works are great resources when you are looking for overview information on a topic. These resources often include a list of additional sources for even more information.
Here are two collections of general reference works and encyclopedias available online.
Connect to Gale Virtual Reference
Online collection of specialized subject encyclopedias.
Connect to Credo Reference Online
More than 600 reference books, across subject areas, speciaized Topic pages, videos, mind-maps, and links to journal articles.