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@article{MT_1987_9_a5, author = {E. P. Volokitin and S. A. Treskov}, title = {A variant of the bifurcation of a fourfold equilibrium state with two zero eigenvalues}, journal = {Matemati\v{c}eskie trudy}, pages = {60--66}, publisher = {mathdoc}, volume = {9}, year = {1987}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MT_1987_9_a5/} }
E. P. Volokitin; S. A. Treskov. A variant of the bifurcation of a fourfold equilibrium state with two zero eigenvalues. Matematičeskie trudy, Tome 9 (1987), pp. 60-66. http://geodesic.mathdoc.fr/item/MT_1987_9_a5/