Guevara Guerrero, M., and R. Puche Navarro. “The Emergence of Cognitive Short-Term Planning : Performance of Preschoolers in a Problem-Solving Task”. Acta Colombiana de Psicología, vol. 18, no. 2, Oct. 2015, pp. 13-27, doi:10.14718/ACP.2015.18.2.2.