Both have great sources, so either of them would be great. However, there are pros and cons to both. The library would be a bit more time consuming because you'd have to find the book and the flip through each individual page to find what you're looking for. But 9/10 the resource is reliable, and you can verify that by looking at the author, publisher, year of publishing, etc. With the internet, you can find everything you're looking for with the click of a button, but it's much harder to verify if that source is reliable. I'd suggest for online research purposes, make sure you stray away from websites like Wikipedia, be sure your source has an author and a date, or use https://scholar.google.com/
