Title An improved upper bound on the double Roman domination number of graphs with minimum degree at least two Type of Research Article Keywords An improved upper bound on the double Roman domination number of graphs with minimum degree at least two Abstract An improved upper bound on the double Roman domination number of graphs with minimum degree at least two Researchers Rana Khoeilar (First Researcher)، hossein karami (Second Researcher)، Mustapha Chellali (Third Researcher)، Seyed Mahmoud Sheikholeslami Kavkani (Fourth Researcher)