@article{DAN_1969_186_3_a20,
     author = {L. P. Vinnik and A. V. Nikolaev},
     title = {Microstructure of longitudinal wave travel time curve},
     journal = {Doklady Akademii Nauk},
     pages = {571--574},
     publisher = {mathdoc},
     volume = {186},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_186_3_a20/}
}