Search by keyword and then use the options in the left-hand menu of the result list to the "Collection" to "Carleton College Reference" or to limit the "Material Type" to "Reference Entries" to find reference articles in Carleton's online and print reference books.

For example, try: stratification

Academic reference sources are a great set of tools to use alongside article databases. Consulting a signed article is like asking an expert about a topic. Use these short articles to get a sense of how research in the field is organized what language is used (gather keywords to improve your searches elsewhere), find ideas for shaping your question, and see vetted lists of books and articles (better than 3,000 results from a search).