1. Wörner J. (2016). Moon Village: a vision for global cooperation and Space 4.0. Available at: http://blogs.esa.int/janwoerner/2016/11/23/moon-village/ (accessed 10 June 2018).
2. United Nations Office for Outer Space Affairs (2010). Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space. Available at: http://www.unoosa.org/pdf/publications/st_space_49E.pdf (accessed 10 June 2018).
3. United Nations Committee on the Peaceful Uses of Outer Space Scientific and Technical Subcommittee & International Atomic Energy Agency (2009). Safety Framework for Nuclear Power Source Applications in Outer Space. Available at: http://www.fas.org/nuke/space/iaea-space.pdf (accessed 10 June 2018).
4. United Nations Committee on the Peaceful Uses of Outer Space (2018). Space Debris Compendium, pp. 48–55. Available at: http://www.unoosa.org/documents/pdf/spacelaw/sd/Space_Debris_Compendium_COPUOS_26-Jan-2018.pdf (accessed 10 June 2018).
5. United Nations Office for Outer Space Affairs (2019). Members of the Committee on the Peaceful Uses of Outer Space. Available at: http://www.unoosa.org/oosa/en/members/index.html (accessed 1 January 2019).