Abdullahi A. A., Kazeem E. L., Abbas U. F., and Hassan M. “ROBUST ORDER IDENTIFICATION OF ARIMA AND GARCH MODELS: STATIONARY AND NON-STATIONARY PROCESS”. FUDMA JOURNAL OF SCIENCES, Vol. 7, no. 3, July 2023, pp. 10 -15, doi:10.33003/fjs-2023-0703-1847.