Newspaper articles, which you may have researched while finding primary sources, are often primary sources. Magazine and journal articles are typically secondary sources, and they are great to reference when you are researching. Depending on when they were written, some magazine and journal articles may be primary sources, too.
It is best to wait to search for articles after you have done a bit of research on background information and in books. You will then have a better idea of what you are looking for.
Please ask Sarah or Jo if you'd like us to see if we can gain access to other specific titles.