V. B. Kir'yanov, V. S. Yarunin, “Superradiant phase transitions of Fermi and bose operators with trilinear interaction”, TMF, 51:3 (1982), 456–464; Theoret. and Math. Phys., 51:3 (1982), 615–620
V. B. Kir'yanov, V. S. Yarunin, “Superradiance for lattice model with Lee interaction”, TMF, 43:1 (1980), 91–99; Theoret. and Math. Phys., 43:1 (1980), 340–345