@article{ZNSL_1990_185_a12,
     author = {O. M. Fomenko},
     title = {Sums of squares in imaginary quadratic {fields.~II}},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {160--167},
     year = {1990},
     volume = {185},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1990_185_a12/}
}