Kubbara، F. S.، و Dueker، K. J. (1992). GEOGRAPHIC DATA IN CITY PLANNING DEPARTMENTS: THE VOLUME AND USERELA TED TO ADVANCEMENTS IN GEOGRAPHIC INFORMATION SYSTEMS (GIS) TECHNOLOGY (رسالة دكتوراه غير منشورة). Portland State University، بورتلاند. مسترجع من http://search.mandumah.com/Record/620035
Kubbara، Fawzi Saeed، و Kenneth J. Dueker. "GEOGRAPHIC DATA IN CITY PLANNING DEPARTMENTS: THE VOLUME AND USERELA TED TO ADVANCEMENTS IN GEOGRAPHIC INFORMATION SYSTEMS (GIS) TECHNOLOGY" رسالة دكتوراه. Portland State University، بورتلاند، 1992. مسترجع من http://search.mandumah.com/Record/620035