Barend Coster was married to the here mentioned Betje van Coevorden. They lived with their daughter Sara. They also had a son Jacob and a daughter Mietje.
Gemeentearchief Rotterdam
In addition, a Jokos file (number 18391) on this household is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.The Jokos file reveals that a claim was lodged for compensation for valuables surrendered to the Lippmann-Rosenthal looting bank (L-claim, number 2283 / 16814).