Tauc, J., et al. “Optical Properties and Electronic Structure of Amorphous Germanium”. Physica Status Solidi (b), vol. 15, no. 2, 1966, pp. 627-3, https://doi.org/10.1002/pssb.19660150224.
Tauc, J., Grigorovici, R., & Vancu, A. (1966). Optical Properties and Electronic Structure of Amorphous Germanium. Physica Status Solidi (b), 15(2), 627-637. https://doi.org/10.1002/pssb.19660150224
Tauc J, Grigorovici R, Vancu A. Optical Properties and Electronic Structure of Amorphous Germanium. physica status solidi (b). 1966;15(2):627-3.