1. “Orbital Debris Mitigation”, NASA Orbital Debris Program Office, accessed 01 July 2015, http://orbitaldebris.jsc.nasa.gov/mitigate/mitigation.html.
2. “Space Debris and Human Spacecraft”, Marc Garcia (editor), National Aeronautics and Space Administration, accessed 01 July 2015, http://www.nasa.gov/mission_pages/station/news/orbital_debris.html.
3. “Gravity (2013) – IMDB”, IMDB.com, accessed 01 July 2015, http://www.imdb.com/title/tt1454468/.
4. Space Debris – Models and Risk Analysis;Klinkrad,2006
5. “Orbital Debris Engineering Models”, NASA Orbital Debris Program Office, accessed 01 July 2015, http://orbitaldebris.jsc.nasa.gov/model/engrmodel.html.