@article{DAN_1978_243_1_a20,
     author = {Z. A. Steingrad},
     title = {Einstein--Maxwell equation system and the calibration of four vector of the electromagnetic field},
     journal = {Doklady Akademii Nauk},
     pages = {85--88},
     publisher = {mathdoc},
     volume = {243},
     number = {1},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_243_1_a20/}
}