Paris Pamfilos, The associated harmonic quadrilateral,
Forum Geometricorum, 14 (2014) 15--29.

Abstract. In this article we study a natural association of a harmonic quadrilateral to every non-parallelogrammic quadrilateral. In addition we investigate the corresponding association in the case of cyclic quadrilaterals and the reconstruction of the quadrilateral from its harmonic associated one. Finally, we associate to a generic quadrilateral a cyclic one.

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