@article{ZNSL_2001_276_a15,
     author = {O. M. Fomenko},
     title = {Class numbers of indefinite binary quadratic forms},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {312--333},
     year = {2001},
     volume = {276},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2001_276_a15/}
}