[1]
E. A. Girik, “On the existence of vector fields with a given set of singular points on a two-dimensional closed oriented manifold”, Ukr. Mat. Zhurn., vol. 45, no. 12, pp. 1706–1709, Dec. 1993, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5980