Multivalued groups and Newton polyhedron
V. G. Bardakov, T. A. Kozlovskaya

Список литературы
1.	V.M. Buchstaber, “$n$-valued groups: theory and applications”, Mosc. Math. J., 6:1 (2006), 57–84
2.	V.M. Buchstaber, S.P. Novikov, “Formal groups, power systems and Adams operators”, Mat. Sb., N.Ser., 84(126) (1971), 81–118