Thomas A. Carlson (eds.), "Abgar" in The Gorgias Encyclopedic Dictionary of the Syriac Heritage last modified September 4, 2013, http://syriaca.org/bibl/19
    
        
            
                
                    
                        L.
                        Van Rompay
                    
                    Abgar
                
        
                
                    
                        
                            Sebastian
                            P.
                            Brock
                        
                    
                    
                        
                            Aaron
                            M.
                            Butts
                        
                    
                    
                        
                            George
                            A.
                            Kiraz
                        
                    
                    
                        
                            Lucas
                            Van Rompay
                        
                    
                    The Gorgias Encyclopedic Dictionary of the Syriac Heritage
                    http://syriaca.org/bibl/1
                    
                        Gorgias Press
                        Piscataway, NJ
                        
                        2011
                    
                    5
                
                http://syriaca.org/bibl/19