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Wellesley College Research Guides

Find Sources

Reference or background sources such as encyclopedias 
pack a lot of info into simple, easy-to-use packages.

We can help you find background sources that get an overview of a topic, look of factual information, give you ideas for keywords, get bibliographies for more high-quality sources, and more.

Types of Reference Sources


Encyclopedias attempt to provide comprehensive summaries of knowledge in either a specific field (subject encyclopedias) or "everything" (general encyclopedias).

Encyclopedias are typically divided into a collection of articles on discrete topics. Academically oriented encyclopedias will often include short bibliographies, making them a good resource for identifying key books and articles on a topic.

Wikipedia Project logo


Wikipedia is a crowdsourced, freely accessible online encyclopedia. Because new articles and edits to existing articles can be made by any user, Wikipedia articles develop at different paces and are, therefore, not created equal. (Read more about how the quality of a Wikipedia article is graded.) Under most circumstances you would not cite an encyclopedia (or a Wikipedia) article, but good quality articles will have citations that you can use to lead you to sources which you can cite.


Dictionaries define words. Larger dictionaries can also include pronunciations and etymologies (the origin of words and how their use has changed over time). Some specialized types include:

  • Subject dictionaries: define technical terms in specific fields, sometimes in as much detail as an encyclopedia

  • Bilingual dictionaries: define words in a different language

  • Thesauri: provide synonyms

  • Rhyming dictionaries

Handbooks and Manuals

Handbooks are sources which gather useful facts, terminology, and standards related to a specific field or profession. They're particularly common in the sciences, where they include formulas, constants, lab procedures, and medical protocols.

Almanacs and Yearbooks

Almanacs and yearbooks summarize the current state of the world, a nation, an organization, an industry, or other topic. They often include statistics; in the case of statistical yearbooks, that's all they have.