Experimental Evidence of Hidden Topological Surface States in PbBi4Te7 / T. Okuda, T. Maegawa, M. Ye [et.al.] // Physical Review Letters. 2013. Vol. 111, № 20. P. 206803-1-206803-5. URL: http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000467815