@article{ZNSL_2000_263_a2,
     author = {E. P. Golubeva},
     title = {Spectrum of {Levy} constants for quadratic irrationalities},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {20--33},
     year = {2000},
     volume = {263},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2000_263_a2/}
}