Holstein, 1959, Ann. Phys. (N.Y.), 8, 325, 10.1016/0003-4916(59)90002-8
Holstein, 1959, Ann. Phys. (N.Y.), 8, 343, 10.1016/0003-4916(59)90003-X
Allock, 1956, Advanc. Phys., 5, 412, 10.1080/00018735600101215
Morin, 1954, Phys. Rev., 93, 1195, 10.1103/PhysRev.93.1195
Heikes, 1957, J. Chem. Phys., 26, 582, 10.1063/1.1743350
Zilberman, 1956, Soviet Phys—JETP, 2, 650
Holstein, 1961, Phys. Rev., 124, 1329, 10.1103/PhysRev.124.1329