@article{VMUMM_2003_6_a6,
     author = {S. S. Marchenkov},
     title = {Closure operators with predicate branching},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {37--39},
     publisher = {mathdoc},
     number = {6},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2003_6_a6/}
}