Roohollah, Hamid y Mahdi (2018) «Index of difficulty which is an Effective Factor on especial Skill Formation in Basketball Free Throw: Index of learning difficulty hypothesis», Revista Publicando. "Quito, Ecuador", 5(16 (2), pp. 50-62. Disponible en: https://revistapublicando.org/revista/index.php/crv/article/view/1647 (Accedido: 27abril2024).