Kaethe Danziger (geb. Halberstaedter)’s "Bertha Gassmann's cousins" notes - name and relation to his father;
MT's research - same name and father, plus mother and date of birth;
sbc.org.pl - Der Oberschlesische Wanderer, Jg. 64, Nr. 268, 18 November 1891;
cbj.jhi.pl - residence card.