Britannica Library

Britannica Online Reference Center and Britannica Online for Kids.
The adult edition includes information from the reliable, authoritative source, Encyclopedia Britannica, with all of the articles in the print set, plus a dictionary, world atlas, notable quotations, current magazine and journal articles, and live news feeds.
The other version is for elementary, middle, and high school students.  It includes two encyclopedias, a dictionary, interactive timelines, world atlas, video clips for school projects, age-appropriate magazine articles, recommended websites, and live news feeds.

Britannica Original Sources

Original Sources is a compilation of thousands of primary source documents, complete books, and authentic images. Students, teachers, and parents have instant access to an online library full of the creations and discoveries of history’s greatest minds as recorded in the authors’ original words.

World Book Online

World Book Online delivers a progressive sequence of core databases supported by supplemental tools, such as language translation, graphic organizers, and unique Webquests. … World Book combines cutting-edge technology with traditional editorial excellence to produce authoritative, trustworthy, and unbiased content.  One login will access four databases, one even in Spanish!