1. NASA's Eyes. URL: https://en.wikipedia.org/wiki/NASA%27s_Eyes (accessed 24.01.2020).
2. Unity. URL: https://unity.com/ (accessed 24.01.2020).
3. Engineering DOUG Graphics for Exploration (EDGE). URL: https://software.nasa.gov/featuredsoftware/edge (accessed 24.01.2020).
4. UNIGINE. URL: https://unigine.com/ (accessed 24.01.2020).
5. Google Earth. URL: https://earth.google.com/web (accessed 24.01.2020).