Mietje Polak was a daughter of Levi Polak and Marianna Loonstein. She married 13 July 1911 in Amsterdam to a non-Jewish man, who has survived the war.
Her siblings, who did not survive the Holocaust too, were Emanuel, Flora, Isidore, George, Esther and Duifje.
City Archive of Amsterdam, archive card of Marianna Loonstein and Mietje Polak.