https://www.maxvandam.info/humo-gen/family/1/F50770?main_person=I134980
Henri Kattenburg (1888 - 1943) - Genealogy (geni.com)
https://archief.amsterdam/indexen/deeds/985333f9-c4fb-56a3-e053-b784100ade19?person=985333f9-c4fc-56a3-e053-b784100ade19