According to a list with shops of Jewish owners, compiled by the Amsterdam police in 1940, this family had a dairy shop, address: Laing's Nekstraat 11 in Amsterdam.
Abstracts of the police archives which are currently at the Amsterdam municipal archives
The Germans ordered Izak de Vries to close down his milk business on 1 November.
See: A.Caransa, Handwerkers Vriendenkring 1869-1942 (Alkmaar 1998) 70
In addition, a Jokos file (number 35551) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.