H. P. Blatt, R. Grothmann, and R. K. Kovacheva, “Sign changes in rational Lw1-approximation”, Ukr. Mat. Zhurn., vol. 58, no. 2, pp. 283–287, Feb. 2006, Accessed: Dec. 06, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3452