Joseph van der Velde was married in Amsterdam on 7 October 1942 to Johanna Elisabeth van Praag, daughter of Abraham van Praag and Sophia Maas..
City Archive of Amsterdam, archive card of Joseph van der Velde and an addition of a visitor of the website .
In addition, Jokos files (numbers 9243, 9244) on this family or other family members are at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.