Jozef Slager was a son of Philip Slager and Jantje Gersons de Jong. He married Diena Berg in 1901 in Holten.
Addition of a visitor of the website
In addition, a Jokos file (number 10647) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.