@book{12772093,
	author = {Kovalev, A. V.},
	title = {Conservation of combined PT symmetry at magnetic phase transitions},
	publisher = {PNPI of NRC "Kurchatov institute"},
	year = {2021},
	series = {Preprint},
	address = {[Гатчина, Ленинградская область]},
	note = {Рез. на рус. яз.}
}