PolulyakhE. O. (2015) “Kronrod–Reeb Graphs of Functions on Noncompact Two-Dimensional Surfaces. I”, Ukrains’kyi Matematychnyi Zhurnal, 67(3), pp. 375-396. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/1990 (Accessed: 4December2024).