@article{ZNSL_1988_168_a1,
     author = {E. P. Golubeva},
     title = {On the period length of the continued fraction expansion of quadratic irrationalities and class numbers of real quadratic {fields.~II}},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {11--22},
     publisher = {mathdoc},
     volume = {168},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1988_168_a1/}
}