Pop, Viorel. “Mathematical Models Issues of Environmental Management”. Studia Universitatis Vasile Goldiș Arad, Seria Științe Economice 25, no. 1 (March 24, 2015): 60-73. Accessed November 25, 2024. https://publicatii.uvvg.ro/index.php/studiaeconomia/article/view/245.