Title A survey on Roman domination parameters in directed graphs Type of Research Article Keywords A survey on Roman domination parameters in directed graphs Abstract A survey on Roman domination parameters in directed graphs Researchers Mustapha Chellali (First Researcher)، Nader Jafari Rad (Second Researcher)، Seyed Mahmoud Sheikholeslami Kavkani (Third Researcher)، Lutz Volkmann (Fourth Researcher)