“Transform the Multivariate to Unitevariate System and Using Elimination and Duplication Matrices with Some Applications” (2021) Journal of Al-Rafidain University College For Sciences ( Print ISSN: 1681-6870 ,Online ISSN: 2790-2293 ), 30(2), pp. 35–47. doi:10.55562/jrucs.v30i2.364.