Haverkort, M. W., Hu, Z., Tanaka, A., Reichelt, W., Streltsov, S. V., Korotin, M. A., et al. (2005). Orbital-Assisted Metal-Insulator Transition in VO2. Physical Review Letters, 95(19): 196404, pp. 1-4. doi:10.1103/PhysRevLett.95.196404.