Hendrika Walvis was a daughter of Hartog Walvis and Rosette van Beetz. She married on 21 July 1910 in Amsterdam to Salomon Kesnig, son of Solomon Kesnig and Mary Ann van Bezema.
City Archive of Amsterdam, archive card of Salomon Kesnig.
In addition, a Jokos file (number 8478) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.