@article{KUKZ_1990_25_25_a0,
     author = {F. G. Avkhadiev},
     title = {Metrics with variable density, and inverse boundary value problems},
     journal = {Trudy seminara po kraevym zada\v{c}am},
     pages = {3--23},
     publisher = {mathdoc},
     volume = {25},
     number = {25},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/KUKZ_1990_25_25_a0/}
}