@article{ZNSL_1981_111_a11,
     author = {T. E. Safonova},
     title = {Updating an optimal structured scheme},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {151--161},
     year = {1981},
     volume = {111},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1981_111_a11/}
}