@article{DAN_1978_238_1_a3,
     author = {M. M. Lavrent'ev and B. Imomnazarov},
     title = {Strongly positive operators},
     journal = {Doklady Akademii Nauk},
     pages = {23--25},
     publisher = {mathdoc},
     volume = {238},
     number = {1},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_238_1_a3/}
}