Jonathan Cohen married Rosette Nijkerk in 1919 in Zaandam. She died in 1935. They had the three here mentioned children. In 1937 Jonathan Cohen remarried Elisabeth Nijkerk, the sister of his deceased wife.
Stadsarchief Amsterdam, archiefkaart Jonathan Cohen
In addition, a Jokos file (number 50383) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.