SUÁREZ-FONTANELLA, D.; CABO-MONTES DE OCA, A.. About the Upstream Contamination. Revista Cubana de Física, [S.l.], v. 36, n. 1, p. 8-14, july 2019. ISSN 2224-7939. Available at: <http://revistacubanadefisica.org/index.php/rcf/article/view/637>. Date accessed: 23 oct. 2019.