Randla, Tiina, and Raivo Vilu. “THE PROBLEMS ON ESTIMATION OF THE RATE OF SUSTAINABILITY”. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 20, 1999): 151–152. Accessed April 24, 2025. https://journals23.rta.lv/index.php/ETR/article/view/1882.