Roosje Grootkerk was the daughter of Isaac Grootkerk en Rebecca de Jong. She was first married to Abraham van der Kar, with whom she had nine children. After he died she was married to Mozes van der Kar. They got two more children. No one of this family survived the war.
Addition of a visitor of the website
See: I. Lipschits, Onbestelbaar. Herinneringen in briefvorm (The Hague 1992) 60