On -chordal polygons.
On Lenz's problem on the independence of the axioms of affine space
On Lorentz-Minkowski geometry in real inner product spaces.
On mappings preserving a single Lorentz-Minkowski-distance in Hjelmslev's classical plane.
On Mathon's construction of maximal arcs in Desarguesian planes.
On M.D.S. codes, arcs in PG(n,q) with q even, and a solution of three fundamental problems of B. Segre.
On median point of the system of elements of -structure
On metric products
On minimum size blocking sets of external lines to a quadric in .
On moduli of expansion of the duality mapping of smooth Banach spaces.
On Moser's Problem of Accommodating Closed Curves in Triangles.
On multiple nuclei and a conjecture of Lunelli and Sce.
On n-ary equivalence relations and their application to geometry [Book]
On non-localized oriented angles
On Norm Three Vectors in Integral Euclidean Lattices. I.
On one construction of all quasifields of order 9
On opposite angle points in isotropic triangle geometrics. (Zu den Winkelgegenpunkten der isotropen Dreiecksgeometrie.)
On optimal linear codes over .
On orthogonality in nets
On ovoids of .