Hepp, Klaus; Lieb, Elliott H. (1973). "On the superradiant phase transition for Molecules in a Quantized Radiation Field: Dicke Maser Model". Annals of Physics. 76 (2): 360–404. Bibcode:1973AnPhy..76..360H. doi:10.1016/0003-4916(73)90039-0.
Emaljanov, V. I.; Klimontovicz, Yu. L. (1976). "Appearance of Collective Polarisation as a Result of Phase Transition in an Ensemble of Two-level Atoms Interacting Through Electromagnetic Field". Physics Letters A. 59 (5): 366–368. Bibcode:1976PhLA...59..366E. doi:10.1016/0375-9601(76)90411-4.
Hepp, Klaus; Lieb, Elliott H. (1973). "On the superradiant phase transition for Molecules in a Quantized Radiation Field: Dicke Maser Model". Annals of Physics. 76 (2): 360–404. Bibcode:1973AnPhy..76..360H. doi:10.1016/0003-4916(73)90039-0.
Emaljanov, V. I.; Klimontovicz, Yu. L. (1976). "Appearance of Collective Polarisation as a Result of Phase Transition in an Ensemble of Two-level Atoms Interacting Through Electromagnetic Field". Physics Letters A. 59 (5): 366–368. Bibcode:1976PhLA...59..366E. doi:10.1016/0375-9601(76)90411-4.