1. Zephyr, the High Altitude Pseudo-Satellite, AIRBUS Defense and Space,
http://defence.airbus.com/
portfolio/uav/zephyr.
2. G. Romeo, G. Frulla, and E. Cestino, Design of a high-altitude long-endurance solar-powered unmanned air vehicle for multi-payload and operations, J. of Aerospace Engineering, Proc. IMechE Vol. 221 Part G, September 2006
3. NASA, NASA Armstrong Fact Sheet: Helios Prototype,
https://www.nasa.gov/
centers/armstrong/news/FactSheets/FS-068-DFRC.html.
4. Facebook Inc., Aquila drone,
https://www.youtube.com/
watch?v=NzLkmcduYuc.
5. Solar Impulse SA 2016, Solar Impulse,
http://www.solarimpulse.com/
.