Alberto, M., y B. Farruggia. «Evaluation of Polyethylene Glycol Phosphate Aqueous Two-Phase Systems in Purifying Pepsin from Residues of the Slaughter House». Cuban Journal of Agricultural Science, vol. 50, n.º 3, diciembre de 2016, https://cjascience.com/index.php/CJAS/article/view/639.