@article{AA_1990_2_1_a0,
     author = {A. N. Andrianov},
     title = {Multiplicative properties of solutions of quadratic {Diophantine} problems},
     journal = {Algebra i analiz},
     pages = {3--46},
     publisher = {mathdoc},
     volume = {2},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1990_2_1_a0/}
}