Sadi Abu-Saymeh, Mowaffaq Hajja, and Hassan Ali ShahAli, Another
variation on the Steiner-Lehmus theme,
Forum Geometricorum, 8 (2008) 131--140.
Abstract: Let the internal angle bisectors BB' and CC' of angles B and C
of triangle ABC be extended to meet the circumcircle at B* and C*. The Steiner-Lehmus
theorem states that if BB'=CC', then AB=AC. In this article, we investigate
those triangles for which BB*=CC* and we address several issues that arise
within this investigation.