"Directing Airplanes by Wireless". Telephony. 77 (8). Chicago, IL: Telephony Publishing Corp.: 20 August 23, 1919. Archived from the original on October 1, 2021. Retrieved November 24, 2020.
"NextGen Avionics Roadmap"(PDF). Joint Planning and Development Office. September 30, 2011. Archived from the original(PDF) on April 17, 2012. Retrieved January 25, 2012.
"Directing Airplanes by Wireless". Telephony. 77 (8). Chicago, IL: Telephony Publishing Corp.: 20 August 23, 1919. Archived from the original on October 1, 2021. Retrieved November 24, 2020.
"NextGen Avionics Roadmap"(PDF). Joint Planning and Development Office. September 30, 2011. Archived from the original(PDF) on April 17, 2012. Retrieved January 25, 2012.