@article{AA_2003_15_4_a6,
     author = {V. A. Malyshev},
     title = {Periods of quadratic irrationalities, and torson of elliptic curves},
     journal = {Algebra i analiz},
     pages = {177--203},
     publisher = {mathdoc},
     volume = {15},
     number = {4},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2003_15_4_a6/}
}