According to the Sterbebücher of Auschwitz Arnold Stoppelman died on 23 August 1942. It is possible this date is different from the official day of death as established after the war by the Dutch Department of Justice
In addition, a Jokos file (number 14183) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.