Marcus Susan and Judith de Vries married in 1903 in Zaandam. They had four children, among whom Susanna, Karel Elkan, and Jeanette.
Stadsarchief Amsterdam, archiefkaart Marcus Susan
In addition, a Jokos file (number 17362) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.The Jokos file reveals that a claim was lodged for compensation for valuables surrendered to the Lippmann-Rosenthal looting bank (L-claim, number 11715/1826).