Mordechai Kosman, son of Raphael Kosman and Vrouwtje Reens, married Sara Swart, the second child of Marcus Swart and Betje van Beezem, on 8 April 1920. The couple had eight children: Flora, Grietje, Marcus, Raphaël, Margaretha, Rebecca, Mathilda and a child who survived the war. The following documents pertaining to the family remain:
copies of the birth certificate of Sara Swart and the wedding certificate of Mordechai Kosman and Sara Swart; a copy of the ketubah of the chuppah of Mordechai Kosman and Sara Swart; copies of the birth certificates of Grietje Kosman, Marcus Kosman, Raphaël Kosman, Margaretha Kosman, Rebecca Kosman and Mathilda Kosman.
In addition, Jokos files (numbers 36244, 36245) on this family or other family members are at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.