Isaac Abraham was the widower of Klaartje Konijn, who died in 1939 in Amsterdam. He lived also on the Muiderstraat 4a-I in Amsterdam.
Addition of a visitor of the website
In addition, a Jokos file (number 15987) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.