Don, source material comes in many forms. It can be official documents, like for instance UN resolutions, or government documents. It can be memoirs and autobiographies, it can be papers, essays, articles and books written by participants giving accounts of their direct experience, eye witnesses accounts. It can be scientific papers or journals, legal documents, treaties, correspondences between people (for instance, letters from Thomas Jefferson to George Washington would be considered source material). Source material is what journalists are supposed to get their information from. It seems to me that if you are familiar with the process of gathering news, you ought to know this.

Here's an example of source material. It's an essay written by two of the high level negotiators in the peace process that included Camp David in 2000 and ended after Taba. It has not passed through the filter of any news media. It comes directly from the source...

http://www.nybooks.com/articles/15502