Which business that includes Dursun Aydın Özbek is located in Istanbul?
Dursun Özbek: Dursun Aydın Özbek (born 25 March 1949) is a Turkish businessman. Dursun Özbek:  He is the chairman of Galatasaray S.K.. Galatasaray S.K.: Galatasaray Spor Kulübü (] , "Galatasaray Sports Club") is a Turkish sports club based on the European side of the city of Istanbul in Turkey, most notable for its association football department.
Galatasaray S.K.