The Nonexistence of Certain Topological Polygons.
The projective interpretation of the eight 3-dimensional homogeneous geometries.
The Skew-Hyperbolic Motion Group of the Quaternion Plane.
Topological and smooth unitals.
Topological pseudo-ovals, elation Laguerre planes, and elation generalized quadrangles.
Topologische desarguessche Ebenen (Char. ... 2) im spiegelungsgeometrischen Aufbau
Topologische Möbiusebenen in spiegelungsgeometrischer Darstellung
Topology and dimension of stable planes: On a conjecture of H. Freudenthal.