The Feuerbach point and the Fuhrmann triangle
The author proves several results about circles passing through the Feuerbach point of a given triangle as well as their relations to the Fuhrmann triangle. In particular, he shows that the Fuhrmann triangle is perspective with the circumcevian triangle of the incenter, with the perspectrix being the tangent to the nine-point circle at the Feuerbach point.
scientific article; zbMATH DE number 6628778