This person is commemorated on a memorial in Sneek. More information on this memorial can be found (in Dutch) on the website of the Nationaal Comité 4 en 5 mei.
Widow Frederika Mendelson-Onderwijzer and her family
In addition, a Jokos file (number 51240) 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 8186/4287).