“…xvii This article highlights further research by the authors, begun in [16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33]. The focus of the article "Irreversibility of financial time series: a case of crisis" [34] by Andrii O. Bielinskyi, Serhii V. Hushko (figure 5), Andriy V. Matviychuk, Oleksandr A. Serdyuk, Serhiy O. Semerikov and Vladimir N. Soloviev to measure the varying irreversibility of stock markets.…”