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3. Encyclopædia Britannica: History of Radar, www.britannica.com/technology/radar/History-of-radar, Accessed 11 July 2021
4. Wikipedia: Rudolf Kühnhold, https://de.wikipedia.org/wiki/Rudolf_Kühnhold, Accessed 11 July 2021
5. Wikipedia: Jagdschloss radar, https://en.wikipedia.org/wiki/Jagdschloss_radar, Accessed 11 July 2021