Helly, J., Cole, S., Frenk, C., Baugh, C., Benson, A., Lacey, C., & Pearce, F. (2003). A comparison of gas dynamics in smooth particle hydrodynamics and semi-analytic models of galaxy formation. Monthly Notices of the Royal Astronomical Society, 338(4), 913-925. https://doi.org/10.1046/j.1365-8711.2003.06152.x