Reference resources are a great place to begin your research. They can help you define terms as well as to find background information about a topic, a chronicle of its history, theories, key people and sometimes a bibliography of additional sources.
There are many different types of reference sources, which include dictionaries, encyclopedias, thesauri, bibliographies, handbooks, style manuals to name a few.
To find encyclopedias or dictionaries on your topic, search Omni using the keywords of your topic combined with "encyclopedia" or "dictionaries".
Oxford Reference Online - History
♦ Dictionary of British History
♦ Oxford Dictionary of the Middle Ages
♦ Oxford Dictionary of the Renaissance
♦ Encyclopedia of the Middle Ages.