Boshkov, Tatjana. “OPTIMAL LINEAR AND NON-LINEAR LABOR INCOME TAXATION: A CRITICAL SURVEY”. Challenges of Tourism and Business Logistics in the 21st Century 5, no. 1 (June 6, 2022): 16–32. Accessed September 25, 2026. https://js.ugd.edu.mk/index.php/YFNTS/article/view/5132.