An interesting insight into the earlier contribution of Kyiv-born Vadim Berezinskii, which was among discoveries that led to the 2016 Nobel Prize in Physics: “One year before the work of Kosterlitz and Thouless, Vadim Berezinskii (died in 1980) also recognized the importance of vortex excitations in the XY-model [8, 9]. He understood that they could drive a phase transition, but did not correctly describe the nature of this finite temperature transition…”