Nowel, Aleksandra, and Zbigniew Szafraniec. “On Trajectories of Analytic Gradient Vector Fields on Analytic Manifolds”. Topological Methods in Nonlinear Analysis 25, no. 1 (March 1, 2005): 167–182. Accessed July 22, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2005.008.