@article{DAN_1975_223_3_a15,
     author = {S. F. Soprunov},
     title = {Initial segments of nonstandard arithmetics},
     journal = {Doklady Akademii Nauk},
     pages = {576--577},
     publisher = {mathdoc},
     volume = {223},
     number = {3},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_223_3_a15/}
}