@article{DAN_1980_250_1_a0,
     author = {V. D. Batukhtin and L. A. Mayboroda},
     title = {On a formalization of extremal problems},
     journal = {Doklady Akademii Nauk},
     pages = {11--14},
     publisher = {mathdoc},
     volume = {250},
     number = {1},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1980_250_1_a0/}
}