Ljumović, I., and I. Lečovski-Milojkić. “DEVELOPMENT OF ECOTOURISM IN SERBIA: THE IMPORTANCE OF ORGANIC FARMS”. Tourism International Scientific Conference Vrnjačka Banja - TISC, Vol. 2, no. 1, June 2017, pp. 605-22, http://www.tisc.rs/proceedings/index.php/hitmc/article/view/163.