Gallo, L. C., Fabian, A. C., Boller, T., & Pietsch, W. (2005). A possible line-like emission feature at 8 keV in the Seyfert 1.2 UGC 3973. Monthly Notices of the Royal Astronomical Society, 363(1), 64-70. doi:10.1111/j.1365-2966.2005.09418.x.