Dal Jang, Y., M. D. Lindemann, E. van Heugten, R. D. Jones, B. Gyun Kim, C. V. Maxwell, and J. S. Radcliffe. “Effects of Phytase Supplementation on Reproductive Performance, Apparent Total Tract Digestibility of Ca and P and Bone Characteristics in Gestating and Lactating Sows”. Revista Colombiana De Ciencias Pecuarias, Vol. 27, no. 3, July 2014, pp. 178-93, https://revistas.udea.edu.co/index.php/rccp/article/view/324891.