Libin, I., Seara Vazquez, M., Oleinik, T., Pérez Peraza, J., Treyger, E. International Journal of Applied and Basic Research”, M., № 9, 71-72, 2012
Libin IJ, Ceará M. Vázquez, Oleinik TL, Pérez Peraza H., O. Sizov, Treyger EM revista
International Journal of Experimental de Educación № 9, 35-38. 2012