Mustapa FH, Ismail MT. Regime-Adaptive ARIMA–GARCH Framework under Structural Break: Evidence from the S&P 500 Index. J. Appl. Sci. Eng. Technol. Educ. [Internet]. 2026 Aug. 31 [cited 2026 Sep. 7];8(2):480-91. Available from: https://ascijournal.eu/index.php/asci/article/view/4894