Otto and Elise Hampel ☞ Wikipedia
List of Germans who resisted Nazism ☞ Wikipedia
The German Resistance Memorial Center ☞ Die Gedenkstätte Deutscher Widerstand
GDW DIGITAL ☞ ☞ Die Gedenkstätte Deutscher Widerstand
Alone in Berlin: the tragic couple who stood up to Hitler ☞ i News
‘My family resisted the Nazis’: why director had to film Alone in Berlin ☞ The Guardian
1943: Elise and Otto Hampel, postcard writers ☞ Executed Today.com