Helly, J., Cole, S., Frenk, C., Baugh, C., Benson, A., & Lacey, C. (2003). Galaxy formation using halo merger histories taken from N-body simulations. Monthly Notices of the Royal Astronomical Society, 338(4), 903-912. https://doi.org/10.1046/j.1365-8711.2003.06151.x