Given name: M Family name: Koenigstein

A doctor, sees patients at a clinic, since November 1940 lives at Nowolipki Street No. 18, flat 5.

Warsaw Telephone Directory 1939 (SASTW - Spis Abonentow Sieci Telefonicznej m.st. Warszawy 1939): K. Marek (the older one), Doctor of Medicine, a laryngologist, Nowogrodzka Street No. 18, telephone number: 7-18-82 and K. M., Krakowskie Przedmiescie Street No. 16-18, telephone number: 2-39-66.