When you have a lot of sources to manage, you can use the tools within Ebsco and Jstor to store your articles and books, but that can be cumbersome. Instead, you might try a manager like Zotero 

With most citation managers, you can import the citation, or the whole pdf, and tell the manager which style you want to use. If you are switching between Chicago Manual of Style and APA, this can be a lifesaver. 

You can also create folders for different topics, or classes. 

There are a number of managers. You can see a list on this page. Zotero is easy to use, but managers like Paperpile work closely with Google docs. Take a look and see if one might benefit you.