Reyes Santiago, A. y González Maiz Jiménez, J. 2023. Machine learning portfolios for US stock prices: Directional forecasting before and during the COVID-19 pandemic. Contaduría y Administración. 69, 4 (nov. 2023), e475. DOI:https://doi.org/10.22201/fca.24488410e.2024.5191.