Isaac Barend married Jetje Braasem in 1926 in Amsterdam. She died in 1934. They had three children: Frederika (who died at a young age) and the here mentioned Samuel and surviving child. Isaac married for a second time in 1935 in Amsterdam. He divorced in 1939. Isaac married for a third time on 11 December 1940 in Amsterdam to Elisabeth Koningswinter. They had a divorce on 28 October 1942.
Stadsarchief Amsterdam, archiefkaarten Isaac Barend en Elisabeth Koningswinter
In addition, a Jokos file (number 14390) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.