As you search, concentrate on finding a variety of genres on your topic. Diverse genres will contribute different types of information and perspectives to help you better understand the topic you are researching.
The sources you choose should represent different rhetorical stances in terms of purpose, audience, type of appeal (ethos, logos, pathos), authority, etc.
Below are different options to find diverse genres.
Academic Search Premier helps you find varied article genres: from newspapers, magazines and scholarly journals.
Newsbank provides articles from over 900 U.S. newspapers