Mullerova, Jarmila, and Pavol Sutta. 2017. “On Some Ambiguities of the Absorption Edge and Optical Band Gaps of Amorphous and Polycrystalline Semiconductors”. Communications - Scientific Letters of the University of Zilina 19 (3), 9-15. http://journals.uniza.sk/index.php/communications/article/view/225.