Mekić, C., G. Trifunović, Z. Novaković, R. Vujić, and D. Romić. “The Rise of Proftability in Sheep Production by Out of Season Induction of Heat in Ewes”. Ekonomika Poljoprivrede, vol. 57, no. Spec.num.2, Dec. 2010, pp. 117-22, https://ea.bg.ac.rs/index.php/EA/article/view/922.