@article{DAN_1960_135_2_a7,
     author = {S. Ya. Havinson},
     title = {Extremum problems for functions satisfying some supplementary restrictions inside the region and the application 
},
     journal = {Doklady Akademii Nauk},
     pages = {270--273},
     publisher = {mathdoc},
     volume = {135},
     number = {2},
     year = {1960},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_135_2_a7/}
}