When you're doing research, it's important to know what TYPE of source you're reviewing. A newspaper article may not be good for a scientific paper, and a magazine article can't take the place of a peer reviewed article. Understanding source types will help you filter out sources you don't need so you can find more of the sources that are useful!
Newspapers (News sources)
Magazines
Academic Journals (Peer-reviewed or scholarly journals)
Trade Publications
Books
Reference Books