Tobias Scheunchen (eds.), "al-Ḥajar - الحجر " in The Beth Qaṭraye Gazetteer last modified January 10, 2020, https://bqgazetteer.bethmardutho.org/place/5034
  
    
      
        
          al-Ḥajar
          الحجر
          
          A town located 55 km from al-ʿUlā in the Medina Region.وبين الحجر والعلا نصف يوم أو دونه
                    
                        26.8061 37.95512
                    
          https://bqgazetteer.bethmardutho.org/place/5034
          http://syriaca.org/place/5034
          http://gazetteer.dainst.org/place/2105911
          
            Riḥlat Ibn Baṭṭūta. Tuḥfat al-nuẓẓār fī gharāʾib al-amṣār wa-ʿajāʾib al-asfār
                        Ibn Baṭṭūta
                        
            127
          
                    
                        http://gazetteer.dainst.org/place/2105911iDAI.gazetteer Deutsches Archäologisches Institute