1. Anosov, D.V.: Nielsen numbers of mappings of nil-manifolds. Uspekhi Mat. Nauk 40(244), 133–134 (1985)
2. Brown, R.: Fixed points of $$n$$-valued multimaps of the circle. Bull. Pol. Acad. Sci. Math. 54(2), 153–162 (2006)
3. Brown, R., Deconinck, C., Dekimpe, K., Staecker, P.C.: Lifting classes for the fixed point theory of $$n$$-valued maps. Topol. Appl. 274, 107125 (2020)
4. Brown, R., Gonçalves, D.: On the topology of $$n$$-valued maps. Adv. Fixed Point Theory 8, 205–220 (2018)
5. Corwin, L.G., Greenleaf, F.P.: Representations of nilpotent Lie groups and their applications. Part I Cambridge studies in advanced mathematics. Cambridge University Press (1990)