@article{DAN_1992_325_4_a2,
     author = {S. G. Leiko},
     title = {Extremals of curve-turn functionals of a {pseudo-Riemannian} space},
     journal = {Doklady Akademii Nauk},
     pages = {659--663},
     publisher = {mathdoc},
     volume = {325},
     number = {4},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1992_325_4_a2/}
}