Tu, Chien-Ming Manifestation of a Second Dirac Surface State and Bulk Bands in THz Radiation from Topological Insulators. [electronic resource] - Scientific reports Sep 2015 - 14128 p. digital Publication Type: Journal Article; Research Support, Non-U.S. Gov't ISSN: 2045-2322 Standard No.: 10.1038/srep14128 doi