https://encyclopedia.ushmm.org/content/en/article/blitzkrieg-lightning-war

https://www.iwm.org.uk/history/the-german-lightning-war-strategy-of-the-second-world-war

https://www.britannica.com/event/World-War-II/German-occupied-Europe

https://www.warhistoryonline.com/war-articles/10-of-the-most-devastating-bombing-campaigns-of-wwii.html?chrome=1

https://encyclopedia.ushmm.org/content/en/article/world-war-ii-key-dates

https://www.pbs.org/wgbh/masterpiece/specialfeatures/world-war-ii-major-events-timeline/#

https://www.npr.org/2013/07/24/204538728/after-wwii-europe-was-a-savage-continent-of-devastation