Repovš, D. and Sharko, V. V. (2012) “$S^1$-bott functions on manifolds”, Ukrains’kyi Matematychnyi Zhurnal, 64(12), pp. 1685-1698. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2691 (Accessed: 24April2024).