Patrakeyev, Igor, and Victor Ziborov. “Using Fuzzy Sets in the Estimation System of the Efficiency of Urban Environment Metabolism (on the Example of Cities of Ukraine)”. Geodesy and Cartography 45, no. 3 (October 25, 2019): 102-109. Accessed July 2, 2020. https://journals.vgtu.lt/index.php/GAC/article/view/7699.