Li, W. F., Rajput, I. R., Xu, X., Li, Y. L., Lei, J., Huang, Q., & Wang , M. Q. (2011). Effects of Probiotic (Bacillus subtilis) on Laying Performance, Blood Biochemical Properties and Intestinal Microflora of Shaoxing Duck. International Journal of Poultry Science, 10(8), 583–589. https://doi.org/10.3923/ijps.2011.583.589