Jacob Corper and Catharina Elsas married in 1915 in Amsterdam.
Stadsarchief Amsterdam, archiefkaart Jacob Corper
In addition, a Jokos file (number 51056) 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 2251/3561).