Strong equality of Roman and perfect Roman Domination in treesZehui Shao, Saeed Kosari, Hadi Rahbani, Mehdi Sharifzadeh and Seyed Mahmoud SheikholeslamiRAIRO-Oper. Res., 56 1 (2022) 381-394DOI: https://doi.org/10.1051/ro/2022005