Sources

References used throughout this publication.

Treaties and institutions

• Convention on International Civil Aviation (Chicago, 1944) and its annexes
• International Air Services Transit Agreement and International Air Transport Agreement (1944)
• Treaty on Open Skies (Helsinki, 1992)
• Tokyo Convention (1963), Hague Convention (1970), Montreal Convention (1971)
• Warsaw Convention (1929) and Montreal Convention (1999)
• International Civil Aviation Organization: icao.int

Government sources

• U.S. Department of State, Division for Transportation Affairs: Open Skies Partners (state.gov)
• NASA Earth Science Project Office: WB-57 aircraft (espo.nasa.gov)

Reference and reporting

• Wikipedia articles: Freedoms of the air; International Civil Aviation Organization; EU–US Open Skies Agreement; Bermuda Agreement; Treaty on Open Skies
• Airforce Technology: E-11A Battlefield Airborne Communications Node (BACN) Aircraft
• Shephard Media: "NG announces Bat line of small UAS" (April 2009); "Northrop Grumman readies Bat UAS for USSOCOM"