Shotov A.P. ,     Kutcherenko I.V. ,     Svistov A.E. ,     Itskevich E.S. ,     Kashirskaya L.M. ,     Pankratov O.A. Resonant band and compositional disorder in narrow gap semiconductors lead-tin-selenide. 18 th Intern. conf. on the Physics Semiconductor. Proc. Stokholm, 1986 , с. P.1819-1822