As usual, see the home page for general sources.
The audio clips of Wesley Frazier, Howard Brennan, Charles Givens, Marrion Baker, Earlene Roberts, Helen Markham, Harold Norman and Nick McDonald are from TV interviews conducted in 1963 and 1964. The Domingo Benavides audio comes from an interview conducted in 1967.
When I read out the words of eyewitnesses myself (eg, Marina Oswald, Ruth Paine, Helen Markham, etc.) I am quoting from their respective appearances before the Warren Commission.
The “poor dumb cop” quote comes from the Warren Commission testimony of William Scoggins.
On the errors of J. Edgar Hoover’s FBI, see (to begin with) The Kennedy Assassination Tapes, edited by Max Holland.
On the importance of “sliding doors moments” in the Kennedy assassination, see David Belin’s discussion of “happenstance” in Final Disclosure.
The quote from Hugh Aynesworth comes from No More Silence: An Oral History of the Assassination of President Kennedy, edited by Larry Sneed.
On the importance of considering Oswald’s “patsy” remark in its proper context, see Vincent Bugliosi’s Reclaiming History -- it was Bugliosi who first got me thinking about this point. John McAdams, especially in his book JFK Assassination Logic, is also excellent on the conspiracist technique of “context-stripping”.