KOYNOVA, Teodora and KOLEVA, Vanya. Visitors’ opinions on the environmental protection in Shumen Plateau Nature Park from the negative anthropogenic impact of a nearby city, Bulgaria. Ecological Questions. Online. 15 June 2021. Vol. 32, no. 3, pp. 59-65. [Accessed 3 July 2024]. DOI 10.12775/EQ.2021.024.