Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DM_1991_3_4_a1, author = {E. A. Mikheeva}, title = {Classification of lower neighborhoods of closed classes in the lattice~$\mathcal L_k$}, journal = {Diskretnaya Matematika}, pages = {3--15}, publisher = {mathdoc}, volume = {3}, number = {4}, year = {1991}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DM_1991_3_4_a1/} }
E. A. Mikheeva. Classification of lower neighborhoods of closed classes in the lattice~$\mathcal L_k$. Diskretnaya Matematika, Tome 3 (1991) no. 4, pp. 3-15. http://geodesic.mathdoc.fr/item/DM_1991_3_4_a1/