1. Ahangar HA, Álvarez MP, Chellali M, Sheikholeslami SM, Valenzuela-Tripodoro JC (2021) Triple roman domination in graphs. Appl Math Comput 391:125444
2. Ahangar HA, Amjadi J, Chellali M, Nazari-Moghaddam S, Sheikholeslami SM (2019) Total roman reinforcement in graphs. Discuss Math Graph Theory 39(4):787–803
3. Ahangar HA, Bahremandpour A, Sheikholeslami SM, Soner ND, Tahmasbzadehbaee Z, Volkmann L (2017) Maximal roman domination numbers in graphs. Util Math 103:2017
4. Beeler RA, Haynes TW, Hedetniemi ST (2016) Double roman domination. Discrete Appl Math 211:23–29
5. Chakradhar P, Reddy PVS (2020) Algorithmic aspects of roman domination in graphs. J Appl Math Comput 64(1–2):89–102