@article{ND_2014_10_4_a3,
     author = {Valery V. Kozlov},
     title = {On rational integrals of geodesic flows},
     journal = {Russian journal of nonlinear dynamics},
     pages = {439--445},
     publisher = {mathdoc},
     volume = {10},
     number = {4},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ND_2014_10_4_a3/}
}