This book is another good source. Besides Seymour Hersh, of course, the work of Ron Ridenhour, who died last year, must be remembered, this book does that. Facing My Lai David L. Anderson (Editor), University Press of Kansas
As does another book with the writing of Ruben Salazar, from U.C. Press and this other one I just found, also from U.C.Press, Aztlan and Viet NAM: Chicano and Chicana Experiences of the War George Mariscal
Michael Pugliese P.S. On this thread anyone read this, "On Killing: The Psychological Cost of Learning to Kill in War and Society by Dave Grossman