@article{DM_2009_21_4_a7,
     author = {V. P. Ilyev},
     title = {Problems on independence systems solvable by the greedy algorithm},
     journal = {Diskretnaya Matematika},
     pages = {85--94},
     year = {2009},
     volume = {21},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_2009_21_4_a7/}
}