[1] Comp. Mat. Sci. 27, 151 (2003) K. Stokbro, J. Taylor, M. Brandbyge, J.-L. Mozos, and P. Ordejón. Comp. Mat. Sci., 27, 151, 2003

[2] Chemical Physics 1-3, 111 (2005) K. S. Thygesen, and K. W. Jacobsen. Chemical Physics, 319, 111, 2005