Toniollo, Gilson Hélio, et al. “Evaluation of Thyroxine (T4) and Progesterone-17-Alpha-OH Circadian Rhythm in Swine Females (Sus Scrofa Domestica - Linnaeus, 1758)”. Brazilian Journal of Veterinary Research and Animal Science, vol. 35, no. 4, Jan. 1998, pp. 195-7, https://doi.org/10.1590/S1413-95961998000400010.