Sources
Member card file of IRG Leipzig on Helena Siegelberg
The member card file of the Israelitic religious community (German abbr. IRG) in Leipzig started in the pre-war period and processed and commented after the war includes basic information about Helena Siegelberg, e.g. an indication of her surviving brother who called himself Henryk Zagora later.
Mitgliedskarte IRGL für Helena Siegelberg, 7.5.4/129829828/ITS Digital Archive, Israelitische Religionsgemeinde Leipzig, online verfügbar unter: https://collections.arolsen-archives.org/de/document/129829828
