@article{DAN_1962_143_3_a16,
     author = {I. G. Portnov},
     title = {A rigorous solution to the problem of freezing when the temperature at a fixed boundary is subject to arbitrary variation},
     journal = {Doklady Akademii Nauk},
     pages = {559--562},
     publisher = {mathdoc},
     volume = {143},
     number = {3},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1962_143_3_a16/}
}