@article{SM_1997_188_4_a0,
     author = {M. L. Gerver and E. A. Kudryavtseva},
     title = {A universal sequence in the~classical travel-time inversion problem},
     journal = {Sbornik. Mathematics},
     pages = {483--536},
     publisher = {mathdoc},
     volume = {188},
     number = {4},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1997_188_4_a0/}
}