N. G. Kalugin, Yu. B. Vasil'ev, S. D. Suchalkin, G. Nachtwei, B. E. Sagol, G. Hein, K. Eberl, “Anisotropic multicomponent terahertz photoconductivity in quantum Hall systems”, Pis'ma v Zh. Èksper. Teoret. Fiz., 76:10 (2002), 729–731; JETP Letters, 76:10 (2002), 625–627
