@article{DAN_1989_309_3_a7,
     author = {N. A. Strelkov},
     title = {Optimal coordinate functions in projection-difference methods,},
     journal = {Doklady Akademii Nauk},
     pages = {550--554},
     year = {1989},
     volume = {309},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_309_3_a7/}
}