This person is commemorated on a memorial in Vierhouten. More information on this memorial can be found (in Dutch) on the website of the Nationaal Comité 4 en 5 mei.
Salomon Polak and Sonja Diamant had another son in 1938, called Adri Philip, who only lived one day. Addition of a visitor of the website
In addition, a Jokos file (number 10293) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.