GrigorchukR. I. and KravchenkoR. (2018) “On the rigidity of rank gradient in a group of intermediate growth”, Ukrains’kyi Matematychnyi Zhurnal, 70(2), pp. 165-176. Available at: http://umj.imath.kiev.ua/index.php/umj/article/view/1548 (Accessed: 29November2020).