Salajpal, Krešimir, et al. “Limits in Extensive Swine Husbandry – a Case Study of Turopolje Pig Production System in Croatia”. Acta Agraria Kaposváriensis, vol. 14, no. 2, Feb. 2010, pp. 215-20, https://journal.uni-mate.hu/index.php/aak/article/view/2004.