Radial functions on free groups and a decomposition of the regular representation into irreducible components. T. Pytlik (1981) Journal für die reine und angewandte Mathematik
Räume primitiver Ideale von Gruppenalgebren. H. Leptin, J. Boidol, J. Schürmann, D. Vahle (1978) Mathematische Annalen
Reciprocity theorems in the theory of representations of groups and algebras [Book] Antoni Wawrzyńczyk (1975)