Eric Danneels, The Intouch Triangle and the OI-line,
Forum Geometricorum, 4 (2004) 125--134.
Abstract: We prove some interesting results relating the intouch triangle
and the OI line of a triangle. We also give
some interesting properties of the triangle center X(57), the homothetic
center of the reference triangle and the orthic
triangle of the intouch triangle.