@article{DAN_1989_305_4_a13,
     author = {Ya. N. Khamidullin},
     title = {On the nature of the geophysical medium discontinuity},
     journal = {Doklady Akademii Nauk},
     pages = {828--830},
     publisher = {mathdoc},
     volume = {305},
     number = {4},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_305_4_a13/}
}