Ayala, L., R. Bocourt, M. Castro, M. Martínez, and M. Herrera. “Effect of the Probiotic Additive Bacillus Subtilis and Their Endospores on Milk Production and Immune Response of Lactating Sows”. Cuban Journal of Agricultural Science, vol. 49, no. 1, Feb. 2016, https://cjascience.com/index.php/CJAS/article/view/550.