S. I. LEE, T. S. LI, and I. H. KIM, “Dietary supplementation of delta-aminolevulinic acid to lactating sows improves growth performance and concentration of iron and hemoglobin of suckling piglets”, Indian J of Anim Sci, vol. 86, no. 7, pp. 781–785, Jul. 2016, doi: 10.56093/ijans.v86i7.59923.