Lin, Wenguang, and Shengxiong Wu. “Predicting S&P 500 Index ETF (SPY) During COVID-19 via K-Nearest Neighbors (KNN) Algorithm”. Journal of Accounting and Finance 23, no. 2 (June 27, 2023). Accessed November 16, 2024. https://mail.articlegateway.com/index.php/JAF/article/view/6149.