Lee, Yen-Hsien, and Hao Fang. “Oil and S&P 500 Markets: Evidence from the Nonlinear Model”. International Journal of Economics and Financial Issues 2, no. 3 (May 8, 2012): 272–280. Accessed January 22, 2025. https://econjournals.com./index.php/ijefi/article/view/201.