@article{TAM_1992_18_1_a2,
     author = {Ranislav Bulatovi\'c},
     title = {An nonstability criterion of equlibrium for nonholonomic system},
     journal = {Theoretical and applied mechanics},
     pages = {21 },
     year = {1992},
     volume = {18},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAM_1992_18_1_a2/}
}