PACS:64.60.Cn DOI:10.1070/PU1991v034n06ABEH002385 URL: https://ufn.ru/en/articles/1991/6/c/ Citation: Kut’in E I, Lorman V L, Pavlov S V "Methods of the theory of singularities in the phenomenology of phase transitions" Sov. Phys. Usp.34 (6) 497–514 (1991)