Helena e Vries was a daughter of David de Vries and Theodora Haringman. She married in Amsterdam on 20 August 1941 to Marcus Blom. Stadsarchief Amsterdam, archiefkaart Helena de Vries.
In addition, a Jokos file (number 31224) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.