Histories of herbicide program

 "The History of Agent Orange Use in Vietnam an Historical Overview from the Veteran's Perspective" by Paul L. Sutton

Operation Ranch Hand Herbicides in Southeast Asia article by William Buckingham

See also the book by William Buckingham: Operation Ranch Hand: The Air Force and Herbicides in South-East Asia 1961 - 1971 

Herbicidal Warfare: The Ranch Hand Project in Vietnam - Paul Frederick Cecil (1986)