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2. Groupes formels associés aux anneux de Witt généralisés;Cartier;C. R. Acad. Sci. Paris A,1967
3. Introduction to the Theory of Formal Groups;Dieudonne,1973
4. The real numbers as a wreath product;Faltin;Adv. in Math.,1975
5. Formal Groups and Applications;Hazewinkel,1978