Grigorov, B., Vassilev, K., Velev, N. and Assenov, A. (2016) “The Contradiction between Taxa of Conservation Significance and Invasive Species – a Case Study of Sustainable Development in Mala Planina”, European Journal of Sustainable Development, 5(4), p. 464. doi: 10.14207/ejsd.2016.v5n4p464.