Herbert J. Strentz, “A Survey of Press Coverage of Unidentified Flying Objects, 1947- 1966” (Ph.D. diss., Northwestern University, 1970), 196-198; 216-217; 224.
Lt. Col. Quintanilla's unpublished manuscript entitled, "UFO’s: An Air Force Dilemma" is available from: http://www.minotb52ufo.com/pdf/Quintanilla-afdilemma.pdf. Gen. Thomas D. White is quoted from the forword to: Tacker, Lawrence J. Flying Saucers and the U.S. Air Force. Princeton, NJ: Van Nostrand Co. 1960. Sec. of the Air Force, Harold Brown is quoted from Strentz based on comments included in: "Unidentified Flying Objects." (No. 55) Electronic Record. Hearing Committee of Armed Services of the House of Representatives. 89th Congress, Second Session. 5 April 1966. (50-066 O) U.S. Government Printing Office: Washington, D.C. 1966.
In addition, see: http://www.isaackoi.com/ufo/19660405-house-armed-services-hearing.html.