LACKO, Roman - HAJDUOVÁ, Zuzana. Determinants of Environmental Efficiency of the EU Countries Using Two-Step DEA Approach. - Registrovaný: Scopus. In Sustainability : [International Journal of Environmental, Cultural, Economic and Social Sustainability]. - Basel : MDPI. ISSN 2071-1050, 2018, vol. 10, no. 10, pp. [1-13] online.