@article{DA_2013_20_2_a6,
     author = {S. S. Marchenkov},
     title = {On maximal and minimal elements in partially ordered sets of {Boolean} degrees},
     journal = {Diskretnyj analiz i issledovanie operacij},
     pages = {88--101},
     publisher = {mathdoc},
     volume = {20},
     number = {2},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DA_2013_20_2_a6/}
}