“On Additive Mapping With Period 3 on Rings and Near-Rings”. Journal of Al-Rafidain University College For Sciences ( Print ISSN: 1681-6870 ,Online ISSN: 2790-2293 ), vol. 42, no. 1, Oct. 2021, pp. 259-73, https://doi.org/10.55562/jrucs.v42i1.168.