Thomas A. Carlson (ed.), "al-Thaghr" in last modified June 30, 2014, http://syriaca.org/place/567
    
        
            
                
                    al-Thaghr
                    الثغر
                    الثَغْر
                    The border area of northern Syria and Mesopotamia between the Byzantine Empire and the caliphate.
                    
                        Attestation of name الثَغْر in the Muʿjam al-buldān of Yāqūt al-Ḥamawī.
                        
                    
          
                        
                        
                    
                    http://syriaca.org/place/567
                    
                        كتاب اللؤلؤ المنثور في تاريخ العلوم والأداب السريانية
                        
                        511
                    
                    
                        The Scattered Pearls: A History of Syriac Literature and Sciences
                        
                        569
                    
                    
                        Muʿjam al-buldān
                        Yāqūt al-Ḥamawī
                        
                        II:93