1.
Polulyakh EO. Kronrod–Reeb Graphs of Functions on Noncompact Two-Dimensional Surfaces. I. Ukr. Mat. Zhurn. [Internet]. 2015Mar.25 [cited 2024Apr.19];67(3):375-96. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/1990