Schrijver, C. J., Derosa, M. L., Barnes, G., Lites, B., Tarbell, T., McTiernan, J., et al. (2008). Nonlinear force-free field modeling of a solar active region around the time of a major flare and coronal mass ejection. Astrophysical Journal, 675, 1637-1644. doi:10.1086/527413.