This guide will help you throughout the research process.
Use this guide to search the most relevant and credible encyclopedias, databases, books, and web sites.
Also, look for resources on citations and evaluating internet resources.
Much market segmentation and consumer behavior information is a a process of inference. You might not be able to find out exactly how many people in area X desire to buy product Y, but often you can use library resources to get a sense of likely consumers, market trends, headwinds, competitors, and more.