The site is sponsored by the National Archives, an agency of the federal government. Books, papers, journal articles, essays, etc. Clearly, letters can be filled with every kind of lie. Those annual reports are still primary sources. It allows the reader to follow your research so that they may come to their own conclusions about your conclusions.
Different disciplines have different ways of citing source materials.
For the purpose of this class, we will usually follow the humanities citation style used in the Columbia Guide to Online Style . You will want to pay especial attention to section 2.15 on that page, which demonstrates how to cite electronic databases, which we will be using quite a bit. For example, suppose you wanted to get at the truth of what happened at Waco, when the Branch Davidians and the Federal Government had their fateful encounter there. Given all the evidence and documents, one can create a narrative or, rather, many different narratives about what happened at Waco. This happens in criminal trials on a daily basis.