2021. Using Markov Chains to Establish the System of Reliability and Preventive Maintenance with Application Part. Journal of Al-Rafidain University College For Sciences ( Print ISSN: 1681-6870 ,Online ISSN: 2790-2293 ). 46, 1 (Oct. 2021), 535–544. DOI:https://doi.org/10.55562/jrucs.v46i1.104.