Ruiz, Gabriel, Natividad Sánchez, and Luis Gonzalo de la Casa. “Pavlov in America: A Heterodox Approach to the Study of his Influence”. The Spanish Journal of Psychology, vol. 6, vol. 6, no. 2, 2003, pp. 99-111, https://revistas.ucm.es/index.php/SJOP/article/view/SJOP0303220099A.