Nikolova, Neli. “ENTREPRENEURIAL ‘BLUE’ PRACTICES FOR SUSTAINABLE DEVELOPMENT AND RESOURCES EFFICIENCY”. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 20, 2019): 198–203. Accessed April 14, 2025. https://journals.rta.lv/index.php/ETR/article/view/4114.