@article{DAN_1977_237_1_a11,
     author = {P. I. Balk},
     title = {On the problems of uniqueness and equivalence in the three-dimensional inverse problem of gravitational potential},
     journal = {Doklady Akademii Nauk},
     pages = {48--51},
     publisher = {mathdoc},
     volume = {237},
     number = {1},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1977_237_1_a11/}
}