Quang Tuan Bui, Pedals on circumradii and the Jerabek center,
Forum Geometricorum, 6 (2006) 205--212.

Abstract: Given a triangle ABC, beginning with the orthogonal projections of  the vertices on the circumradii OA, OB, OC, we construct two triangles each with circumcircle tangent to the nine-point circle at
the center of the Jerabek hyperbola.

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