The “octoid” with triple planar symmetry and its point orbits. (Das dreifach plansymmetrische "Oktoid" und seine Punktbahnen.) Wohlhart, K. — 1995 Mathematica Pannonica
The homogeneous parallel- movement-mechanism. (Der homogene Paralleltrieb-Mechanismus.) Wohlhart, K. — 1991 Mathematica Pannonica