1. On free groups of motions without fixed points;Dekker;Proc. Nederl. Akad. Wetensch,1958
2. Orthogonal isomorphic representations of free groups;de Groot;Canad. J. Math.,1956
3. Lectures in abstract algebra, I;Jacobson,1953
4. Eine kontinuumsmächtige, algebraisch unabhängige Menge reeller Zahlen;Kneser;Bull. Soc. Math. Belg.,1960
5. On free groups of motions and decompositions of the Euclidean space;Mycielski;Fund. Math.,1958