Betje Ritmeester was a daughter of Joseph Ritmeester and Aaltje Brander. She married 30 November 1932 in Amsterdam to George Lodewijk Schrijver, son of Joseph Schrijver and Rebecca Gobetz.
City Archive of Amsterdam, archive card of Joseph Ritmeester and website www.wiewaswie.nl .
In addition, a Jokos file (number 40699) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.