A geometric inequality involving a mobile point in the place of the triangle.
A geometric inequality of the generalized Erdős-Mordell type.
A Geometric Realization Without Self-Intersections Does Exist for Dyck's Regular Map.
A Geometric Theory of Surface Area.
A Geometric Theory of Surface Area.
A Geometric Theory of Surface Area. III.
A mathematical theory of origami constructions and numbers.
A method for establishing certain trigonometric inequalities.
A metric characterization of "spherical" surfaces in n-dimensional hyperbolic space.
A metric induced by the geometric interpretation of Rolle's theorem.
A model of hyperbolic stereometry based on the algebra of quaternions
A new butterfly curve. (Eine neue Schmetterlingskurve.)
A new geometric inequality.
A new line Involution and the Classification Process
A new proof of Morley's theorem
A normed space with the Beckman-Quarles property.
A note on -chordal polygons.
A note on ovals and their evolutoides.
A note on the existence of -equivelar polyhedral maps.
A pair of general triangle inequalities.