@article{VMUMM_1997_4_a5,
     author = {K. Sonin},
     title = {Biregular rings of {Laurent} series},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {20--22},
     year = {1997},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1997_4_a5/}
}