Über die Erzeugung von eigentlichen Transformationsgruppen.
Ueber D-Minimale Aktionen von Zusammen-Haengenden Lie-Gruppen
Uniform Transformation Groups on Lower Dimensional Spaces.
Unifying congruences on S(I).
Union preserving homomorphisms of semigroups of closed relations.
Un'osservazione sugli autoomeomorfismi dei cerchi
Upper semicontinuity of automorphism groups.