What caused the My Lai massacre? 4 pages.
You only have to use one source (the My Lai document book). The book contains an introduction and then documents, most of which are testimonials taken during the investigation in 1969 and 1970. According to the Chicago style, you need to cite both the document and the book (not just the book–unless you’re citing the authors’ introduction in which cases you can just cite the book). For each document, there’s usually a document author, title, and date (not always– use whatever you have). Cite (as footnotes or endnotes) documents in the following format (and remember you only have to give the full book citation once, after that just use an abbreviated title as I did below):
Robert Maples, Testimony to U.S. Army CID, 1969, in My Lai: A Brief History with Documents, eds., James S. Olson and Randy Roberts (Boston: Bedford Books, 1998), 83.
Ernest L. Medina, Testimony to Peers Commission, 1970, in My Lai: A Brief History, 119.