Toniollo GH, Vicente WRR, Oliveira CA de, Malheiros EB, Carvalho MB. Triiodothyronine (T3) and thyronine (T4) serum level evaluation during the oestrus cycle in guilts (Sus scrofa domestica - Linnaeus, 1758). Braz. J. Vet. Res. Anim. Sci. 1998;35(5):210-214. doi:10.1590/S1413-95961998000500003