@article{INTO_1998_60_a9,
     author = {N. P. Osmolovskii and F. Lempio},
     title = {Jacobi conditions and the riccati equation for a~broken extremal},
     journal = {Itogi nauki i tehniki. Sovremenna\^a matematika i e\"e prilo\v{z}eni\^a. Temati\v{c}eskie obzory},
     pages = {187--215},
     publisher = {mathdoc},
     volume = {60},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTO_1998_60_a9/}
}