Watts, Anna L. High Energy Astrophysics, MPI for Astrophysics, Max Planck Society;
Strohmayer, T. E., & Watts, A. L. (2006). The 2004 hyperflare from SGR 1806-20: further evidence for global torsional vibrations. Astrophysical Journal, 653(1 Part 1), 593-601.