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@article{AA_2002_14_3_a2, author = {O. V. Demchenko}, title = {Formal groups over $p$-adic rings of integers with small ramification and distinguished isogenies}, journal = {Algebra i analiz}, pages = {55--85}, publisher = {mathdoc}, volume = {14}, number = {3}, year = {2002}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/AA_2002_14_3_a2/} }
O. V. Demchenko. Formal groups over $p$-adic rings of integers with small ramification and distinguished isogenies. Algebra i analiz, Tome 14 (2002) no. 3, pp. 55-85. http://geodesic.mathdoc.fr/item/AA_2002_14_3_a2/