@article{MM_1998_10_2_a9,
     author = {V. V. Ganina},
     title = {On stability of pendulm's upper equilibrium position},
     journal = {Matemati\v{c}eskoe modelirovanie},
     pages = {110--114},
     publisher = {mathdoc},
     volume = {10},
     number = {2},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MM_1998_10_2_a9/}
}