@article{DAN_1958_120_2_a8,
     author = {\`E. \`E. Tamme},
     title = {On implicit operators},
     journal = {Doklady Akademii Nauk},
     pages = {259--261},
     publisher = {mathdoc},
     volume = {120},
     number = {2},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_120_2_a8/}
}