Also known as scholarly, refereed, peer reviewed, or academic articles.
In general, be sure to use books written for an academic or scholarly audience instead of those written for a popular audience.
E-books provided by library databases can be read online and provide options for searching the entire content of the book so that you can skip directly to the sections of the book focused on your topic.
NOTE: This does not search all of PCC Library's e-book databases.
Videos from reputable publishers are great resources for learning more about a topic. The library provides several databases that include streaming videos, animations, and tutorials.