Murphy, David E.; Sergei A. Kondrashev and George Bailey (1999). Battleground Berlin: CIA vs KGB in the Cold War. New Haven, Connecticut: Yale University Press. ISBN 0-300-07871-4.
Trento, Joe (1999). The Boys from Berlin: The Secret History of the CIA. Boulder, Colorado: Roberts Rinehart Publishers. ISBN 1-57098-315-1.