Graphs with small or large Roman {3}-domination number Nafiseh Ebrahimi, Hossein Abdollahzadeh Ahangar, Mustapha Chellali and Seyed Mahmoud Sheikholeslami RAIRO-Oper. Res., 57 3 (2023) 1195-1208 Published online: 18 May 2023 DOI: 10.1051/ro/2023058