Britannica – provide links to the best Web sites, leading magazines, related books,and the complete Encyclopædia Britannica.

Columbia Encyclopedia - the sixth edition contains nearly 51,000 entries with more than 80,000 hypertext cross-references.

Encarta Free Enclopedia - students can search the free encyclopedia for information.

Encyclopedia.com - Electric Library provides more than 14,000 articles from the Concise Columbia Electronic Encyclopedia.

Fact Monster - reference materials aimed for students that includes an almanac, atlas, dictionary, encyclopedia, and more.

Encyclopedia Smithsonian - features answers to frequently asked questions about the Smithsonian and links to Smithsonian resources on subjects from Art to Zoology.

Kids Click - a web search engine for kids designed by librarians.

Yahooligans Kids' Almanac - a resource written for students about animals, business, disasters, laws, sports, the environment, and more.

High School Hub - provides links appropriate for high school students and a reference section.

Tek Mom Search Tools for Kids - a variety of search engines appropriate for students.

Finding Data on the Internet -  provides links to a variety of sources.

Noodle Quest - asks students a series of questions to help them find appropriate resources.

Tucson-Pima Public Library - provides students the opportunity to reserve books, check the status of their library account and use the reference data base EbscoHost.

Kid's Connect - K-12 students can ask a librarian where to find information on the Internet for a report or project to do for school and get an answer within 2 work days. The students will be given suggestions of good Web sites and other resources to look into for help on their project.

Slate Citation Machine - allows students to enter information from a variety of sources such as books, articles and the Internet and creates an APA or MLA citation

KidsHub - free online learning activities for elementary and middle school students.

Ref desk - a comprehensive list of reference tools.

iTools - easy access to a variety of reference tools.

Info Please - provides links to an assortment of reference tools.

Bartleby - provides search engine to a variety of reference materials.

InfoMine -  contains useful Internet resources to databases, electronic journals, electronic books, bulletin boards, mailing lists, online library card catalogs, articles, directories of researchers, and many other types of information.

Internet Public Library Reference Tools - the University of Michigan provides links to a variety of reference resources.

Awesome Library - provides links to reference materials appropriate for students.

FindArticles.com - provides  published articles from more than 300 journals  to search for free.

Day Pop  - Search 7500 News Sites and Weblogs for Current Events and Breaking News.

American Fact Finder - the U.S. Census Bureau provides tables and maps for all geographies including the U.S., states, counties, cities, towns, American Indian reservations, metropolitan,  areas, zip codes, census tracts, blocks, and more.

CIA World Factbook - provides information, data and maps from the countries all over the world.

Color Landform Atlas of the United States - provides relief maps, county maps, and satellite images, and a map from 1895 for each state in the United States.

Bureau of Justice Statistics -  provides statistics and charts of criminal data.

Find Law -  a law reference  site that provides a  legal subject index, US Federal resources, state resources, cases and codes, and more.

Library of Congress - provides links to Thomas (legislative information),  American Memory (information about US History and Culture), Exhibitions (online galleries) and more.

Map Collections - American Memory from the Library of Congress provides maps from 1500-2002. The collection includes maps of cities and towns, battles, discovery and exploration, cultural landscapes, transportation and communication, and more.

Blank and Outline Maps - provides links to sites with blank maps to different states and countries.

National Geographic Maps - provides detail and blank maps from around the world.

Occupational Outlook Handbook –  a nationally recognized source of career information, designed to provide valuable assistance to individuals making decisions about their future work lives.

Grays Anatomy - the Bartleby.com edition of Gray's Anatomy of the Human Body  features 1,247 vibrant engravings - many in color - from the classic 1918 publication, as well as a subject index with 13,000 entries ranging from the Antrum of Highmore to the Zonule of Zinn.

National Library of Medicine - the United States Library of Medicine provides health and medical information resources and databases including Medline.

CDC National Center for Health Statistics - provides statistical tables, graphs, and charts about health and mortality data.