“Forecasting the Volatility of OPEC Oil Prices Using Fractionally Integrated GARCH Models”. 2025. Journal of Al-Rafidain University College For Sciences ( Print ISSN: 1681-6870 ,Online ISSN: 2790-2293 ) 56 (1): 344-58. https://doi.org/10.55562/jrucs.v56i1.31.