@article{DM_1997_9_4_a6,
     author = {V. A. Shcherbakova},
     title = {Classes of oriented graded graphs with polynomially solvable cardinality {Steiner} problem},
     journal = {Diskretnaya Matematika},
     pages = {73--85},
     publisher = {mathdoc},
     volume = {9},
     number = {4},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_1997_9_4_a6/}
}