TY - JOUR AU - S. V. Agapov AU - D. N. Alexandrov TI - Fourth-Degree Polynomial Integrals of a Natural Mechanical System on a Two-Dimensional Torus JO - Matematičeskie zametki PY - 2013 SP - 790 EP - 793 VL - 93 IS - 5 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/MZM_2013_93_5_a13/ LA - ru ID - MZM_2013_93_5_a13 ER -