Polevoy, Georgiy. «ARTICLE RETRACTED DUE TO PLAGIARISM BY THE AUTHOR Períodos Sensibles De Desarrollo De La Flexibilidad En La Edad Escolar (Sensitive Periods of Flexibility Development at School age): ARTICLE RETRACTED DUE TO PLAGIARISM BY THE AUTHOR». Retos 56 (julio 1, 2024): 1066–1074. Accedido agosto 21, 2025. http://www.revistaretos.org/index.php/retos/article/view/106243.