@article{SM_1969_9_3_a8,
     author = {V. A. Dem'yanenko},
     title = {On~the representation of numbers by binary biquadratic forms},
     journal = {Sbornik. Mathematics},
     pages = {415--422},
     publisher = {mathdoc},
     volume = {9},
     number = {3},
     year = {1969},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1969_9_3_a8/}
}