https://collections.arolsen-archives.org/en/search/person/81974910?s=Halpern%20Ignatz&t=230459&p=1
Holocaust Survivors and Victims Database – Ignatz Halpern (ushmm.org)
Published Lists of Survivors, in German-language newspaper Aufbau, Sept 1944 -Sept 1946 (jewishgen.org)