As many survivors did not live to share their testimonies, Pavel Batel had to gain access to archives to continue his research. In Israel, the Beit Terezín Museum holds a significant collection of documents from Terezín, transferred by Hechalutz right after the war. Additionally, the archive in Litoměřice, where Nazis from Terezín and other collaborators were prosecuted, also provides crucial historical materials for his work.