Chantiratikul, A., et al. “Plasma Selenium Concentration and Glutathione Peroxidase Activity in Red Blood Cells of Laying Hens Fed Sodium Selenite or Zinc-L-Selenomethionine ”. International Journal of Poultry Science, vol. 7, no. 7, June 2008, pp. 692–695, https://doi.org/10.3923/ijps.2008.692.695.