@article{DM_1999_11_4_a7,
     author = {V. G. Il'ichev and O. A. Il'icheva},
     title = {Sign-invariant structures of matrices, and discrete models},
     journal = {Diskretnaya Matematika},
     pages = {89--100},
     publisher = {mathdoc},
     volume = {11},
     number = {4},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_1999_11_4_a7/}
}