Sophia and Esther Blitz were sisters. Together with Alida they were the daughters of Hartog Blitz and Elisabeth van Minden.
Amsterdam Municipal Archives; family card of Esther Blitz
In addition, a Jokos file (number 53318) on this household is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.
Addition