The lack of reversibility during financial crisis and its identification Andrii Bielinskyi, Serhii Hushko, Andriy Matviychuk, Oleksandr Serdyuk, Serhiy Semerikov and Vladimir Soloviev SHS Web Conf., 107 (2021) 03002 Published online: 24 May 2021 DOI: 10.1051/shsconf/202110703002