@article{ZNSL_1991_195_a6,
     author = {P. V. Krauklis and G. Kovalle and L. A. Krauklis},
     title = {On the tomographic study of boundaries of the {Earth} core},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {58--65},
     publisher = {mathdoc},
     volume = {195},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1991_195_a6/}
}