@article{VMUMM_1991_1_a19,
     author = {N. N. Il'inskaya},
     title = {Geometric analysis of a problem on a harmonic oscillator in an ellipse},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {88--92},
     publisher = {mathdoc},
     number = {1},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1991_1_a19/}
}