Mietje Loonstijn was an unmarried daughter of Joseph Loonstijn and Mietje Vos, who have been deceased already before the war. She lived in at the address of her sister Rebecca Loonstijn, who was married in Amsterdam on 6 April 1921 to Mozes Witsenhausen.
City Archive of Amsterdam, archive cards of Mietje Loonstijn and Mozes Witsenhausen.
Biography