1. The 2019 U.S. government orbital debris mitigation standard practices;Liou;Orbital Debris Quarterly News,2020
2. Satellite Database Release 4-1-20, Including Launches through March 31;Union of Concerned Scientists,2020
3. The low LEO protected region: new challenges from large satellite constellations;Anselmo,2020
4. Ideal mix of treaties, guidelines, regulations and industry best practices for space sustainability, 8th Satellites End of Life and Sustainable Technologies Workshop;Oltrogge;Paris, France, January,2020