Even if you find one of these collections, however, I will expect you to do more research on your own to uncover sources not in the book. Background articles are long cover-story type articles that you might not actually use in your paper as examples of argument, but which can be useful in telling you what the major issues are and in giving you dates and names. You should start collecting these articles as soon as possible. In fact, depending on how much you do or don't know about your topic, reading one or more of these background articles might be part of your proposal-writing process. Often you can't really start finding articles until you at least know something about your topic.
News articles are generally short and informative and pretty unbiased.
For the most part you will not want to list or look up these articles as they will be of very little use to you. They will just give you some bits of information, without actually taking a stand. Using them for your argument summaries will inevitably result in a low grade because there is so little to say about them. What you are really looking for is argumentative articles that take a stance on your topic. This is an essential element of your search.