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.

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