<Ul> <Li> Poole, Walter S (2013), Adapting to Flexible Response, 1960--1968, Washington, DC: Office of the Secretary of Defense, 467 pp.; online . </Li> <Li> Wilson, John B. (1998). "XII: Flexible Response". Maneuver and Firepower: The Evolution of Divisions and Separate Brigades . United States Army Center of Military History . CMH Pub 60 - 14 . </Li> </Ul> <Li> Poole, Walter S (2013), Adapting to Flexible Response, 1960--1968, Washington, DC: Office of the Secretary of Defense, 467 pp.; online . </Li> <Li> Wilson, John B. (1998). "XII: Flexible Response". Maneuver and Firepower: The Evolution of Divisions and Separate Brigades . United States Army Center of Military History . CMH Pub 60 - 14 . </Li>

Explain how the idea of flexible response worked against the u.s. in vietnam