BEHAVIOUR OF THE TURKISH URBAN SYSTEM: CORPORATE HEADQUARTERS S. Sence TURK Vedia DOKMECI 1- INTRODUCTION 2- METHODOLOGY 3- BEHAVIOUR OF TURKISH URBAN SYSTEM BY SIZE DISTRIBUTION 4- DISTRIBUTION OF CORPORATE BY SIZE 4.1 Corporate Distribution According to Sales 4.2 Corporate Distribution According to Assets 4.3 Corporate Distribution According to Employments 5-CONCLUSION