Just like there are genres of film and music (drama, comedy or hip hop, classical) or types of writing (persuasive essay, memoir, , there are lots of types of information sources. Where and who publishes an article determines the source type: books, academic journals, trade publications, primary and secondary, popular, premium/subscription and free, educational video, government report, etc. You'll become familiar with a few of the basic types as you continue to engage in research - some are better than others for answering different kinds of questions.