From a previous marriage to Judith Gobits, who died in 1918, Jonas' daughter Marie and another child was born. Clara Susanna is a daughter from Jonas' second marriage to Rebecca Sarfaty. Two of Jonas' sisters, Rosette en Lea, lived with Jonas and his family.
Addition of a visitor of the website
In addition, a Jokos file (number 13957) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.