Abdullahi, Ahmed Abdulazeez, E. Lasisi Kazeem, Umar Farouk Abbas, and M. Hassan. “ROBUST ORDER IDENTIFICATION OF ARIMA AND GARCH MODELS: STATIONARY AND NON-STATIONARY PROCESS”. FUDMA JOURNAL OF SCIENCES 7, no. 3 (July 7, 2023): 10–15. Accessed October 29, 2025. http://www.fjsadmin.fudutsinma.edu.ng/index.php/fjs/article/view/1847.